9781337117562_ppt_ch01.pptxChapter 1An Overview of Compute.docx

9781337117562_ppt_ch01.pptx
Chapter 1
An Overview of Computers and Programming Languages
© 2018 Cengage Learning. All Rights Reserved. May not be
copied, scanned, or duplicated, in whole or in part, except for
use as permitted in a license distributed with a certain product
or service or otherwise on a password-protected website for
classroom use.
C++ Programming: Program Design Including Data Structures,
Eighth Edition
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Objectives (1 of 2)
In this chapter, you will:
Learn about different types of computers
Explore the hardware and software components of a computer
system
Learn about the language of a computer
Learn about the evolution of programming languages
Examine high-level programming languages
Discover what a compiler is and what it does
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Objectives (2 of 2)
Examine a C++ program
Explore how a C++ program is processed
Learn what an algorithm is and explore problem-solving
techniques
Become aware of structured design and object-oriented design
programming methodologies
Become aware of Standard C++, ANSI/ISO Standard C++,
C++11, and C++14
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Introduction
Without software, a computer is useless
Software is developed with programming languages
C++ is a programming language
C++ is suited for a wide variety of programming tasks
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4

A Brief Overview of the History of Computers (1 of 3)
Early calculation devices
Abacus
Pascaline
Leibniz device
Jacquard’s weaving looms
Babbage machines: difference and analytic engines
Hollerith machine
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Early computer-like machines
Mark I
Electronic Numerical Integrator and Calculator (ENIAC)
Von Neumann architecture
Universal Automatic Computer (UNIVAC)
Transistors and microprocessors
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Categories of computers
Mainframe computers
Midsize computers
Micro computers (personal computers)
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Elements of a Computer System
Two main components
Hardware
Software
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Hardware
Central processing unit (CPU)

Main memory (MM) or random access memory (RAM)
Secondary storage
Input/output devices
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Central Processing Unit and Main Memory (1 of 4)
Central processing unit
Brain of the computer
Most expensive piece of hardware
Operations
Carries out arithmetic and logical operations
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FIGURE 1-1 Hardware components of a computer and main
memory

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Random access memory (or main memory) is directly connected
to the CPU
All programs must be loaded into main memory before they can
be executed
All data must be brought into main memory before it can be
manipulated
When computer power is turned off, everything in main memory
is lost
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Main memory is an ordered sequence of memory cells
Each cell has a unique location in main memory, called the
address of the cell
Each cell can contain either a programming instruction or data

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Secondary Storage
Secondary storage: device that stores information permanently
Examples of secondary storage
Hard disks
Flash drives
CD-ROMs
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Input/Output Devices
Input devices feed data and programs into computers
Keyboard
Mouse
Scanner
Camera
Secondary storage
Output devices display results
Monitor

Printer
Secondary storage
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Software
Software are programs written to perform specific tasks
System programs control the computer
Operating system monitors the overall activity of the computer
and provides services such as:
Memory management
Input/output activities
Storage management
Application programs perform a specific task
Word processors
Spreadsheets
Games
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The Language of a Computer (1 of 4)
Analog signals: continuously varying continuous wave forms
Digital signals: sequences of 0s and 1s
Machine language: language of a computer
A sequence of 0s and 1s
Binary digit (bit): the digit 0 or 1
Binary code (binary number): a sequence of 0s and 1s
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Byte: a sequence of eight bits
Kilobyte (KB): 210 bytes = 1024 bytes
ASCII (American Standard Code for Information Interchange)
128 characters
A is encoded as 1000001 (66th character)
The character 3 is encoded as 0110011 (51st character)
Number systems
The decimal system (base 10) is used in our daily life
The computer uses the binary (or base 2) number system
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TABLE 1-1 Binary Units UnitSymbolBits/BytesByte8
bitsKilobyteKB210 bytes = 1024 bytesMegabyteMB1024 KB =
210 KB = 220 bytes = 1,048,576 bytesGigabyteGB1024MB =
210 MB = 230 bytes = 1,073,741,824 bytesTerabyteTB1024 GB
= 210 GB = 240 bytes = 1,099,511,627,776
bytesPetabytePB1024 TB = 210 TB = 250 bytes =
1,125,899,906,842,624 bytesExabyteEB1024 PB = 210 PB =
260 bytes = 1,152,921,504,606,846,976 bytesZettabyteZB1024
EB5 210 EB = 270 bytes = 1,180,591,620,717,411,303,424
bytes
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Unicode is another coding scheme
65,536 characters
Two bytes (16 bits) to store a character
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The Evolution of Programming Languages (1 of 3)
Early computers were programmed in machine language
To calculate wages = rate * hours in machine language:
100100 010001 //Load
100110 010010 //Multiply
100010 010011 //Store
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Assembly language instructions are mnemonic
Instructions are written in an easy-to-remember form
An assembler translates a program written in assembly language
into machine language
Using assembly language instructions, wages = rate * hours can
be written as:
LOAD rate
MULT hours
STOR wages
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High-level languages include Basic, FORTRAN, COBOL, C,
C++, C#, Java, and Python
Compiler: translates a program written in a high-level language
into machine language
In C++, the weekly wages equation can be written as:
wages = rate * hours;
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Processing a C++ Program (1 of 4)
#include <iostream>
using namespace std;
int main()
{
cout << "My first C++ program." << endl;
return 0;
}
Sample Run:
My first C++ program.

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Steps needed to process a C++ program
Use a text editor to create the source code (source program) in
C++
Include preprocessor directives
Begin with the symbol # and are processed by the preprocessor
Use the compiler to:
Check that the program obeys the language rules
Translate the program into machine language (object program)
Use an integrated development environment (IDE) to develop
programs in a high-level language
Programs such as mathematical functions are available
The library contains prewritten code you can use
A linker combines object program with other programs in the
library to create executable code
The loader loads executable program into main memory
The last step is to execute the program
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IDEs are quite user friendly
Compiler identifies the syntax errors and also suggests how to
correct them
Build or Rebuild is a simple command that links the object code
with the resources used from the IDE
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FIGURE 1-2 Processing a C++ program
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Programming with the Problem Analysis–Coding–Execution
Cycle
Programming is a process of problem solving
An algorithm is a step-by-step problem-solving process
A solution is achieved in a finite amount of time

FIGURE 1-3 Problem analysis–coding–execution cycle
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The Problem Analysis–Coding–Execution Cycle (1 of 5)
Step 1: Analyze the problem
Outline the problem and its requirements
Design steps (algorithm) to solve the problem
Step 2: Implement the algorithm
Implement the algorithm in code
Verify that the algorithm works
Step 3: Maintain the program
Use and modify the program if the problem domain changes
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Analyze the problem using these steps:
Step 1: Thoroughly understand the problem and all requirements

Step 2: Understand the problem requirements
Does program require user interaction?
Does program manipulate data?
What is the output?
Step 3: If complex, divide the problem into subproblems
Analyze and design algorithms for each subproblem
Check the correctness of algorithm
Test the algorithm using sample data
Some mathematical analysis might be required
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Once the algorithm is designed and correctness is verified
Write the equivalent code in high-level language
Enter the program using a text editor
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Run code through the compiler
If compiler generates errors
Look at code and remove errors
Run code again through compiler
If there are no syntax errors
Compiler generates equivalent machine code
Link machine code with the system’s resources
Performed by the linker
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Once compiled and linked, the loader can place program into
main memory for execution
The final step is to execute the program
Compiler guarantees that the program follows the rules of the
language
Does not guarantee that the program will run correctly
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Example 1-1 (1 of 2)
Design an algorithm to find the perimeter and area of a
rectangle
The perimeter and area of the rectangle are given by the
following formulas:
perimeter = 2 * (length + width)
area = length * width
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Algorithm
Get the length of the rectangle
Get the width of the rectangle
Find the perimeter with this equation:
perimeter = 2 * (length + width)
Find the area with this equation:
area = length * width
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Calculate each student’s grade
There are 10 students in a class
Each student has taken five tests
Each test is worth 100 points
Design algorithms to:
Calculate the grade for each student and class average
Find the average test score
Determine the grade
Use the provided data: students’ names and test scores
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Algorithm to determine the average test score
Get the five test scores
Add the five test scores
The sum of the test scores is represented by sum
Suppose average stands for the average test score:
average = sum / 5;
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Algorithm to determine the grade:
if average is greater than or equal to 90
grade = A
otherwise
if average is greater than or equal to 80 and less than 90
grade = B
otherwise
grade = C
otherwise
grade = D
otherwise
grade = F
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Main algorithm is presented below:
totalAverage = 0;
Repeat the following for each student:
Get student’s name

Use the algorithm to find the average test score
Use the algorithm to find the grade
Update totalAverage by adding current student’s average test
score
Determine the class average as follows:
classAverage = totalAverage / 10
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Programming Methodologies
Two popular approaches to programming design
Structured
Object-oriented
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Structured Programming
Structured design
Involves dividing a problem into smaller subproblems
Structured programming

Involves implementing a structured design
The structured design approach is also called:
Top-down (or bottom-up) design
Stepwise refinement
Modular programming
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Object-Oriented Programming (1 of 3)
Object-oriented design (OOD)
Identify components called objects
Determine how objects interact with each other
Specify relevant data and possible operations to be performed
on that data
Each object consists of data and operations on that data
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An object combines data and operations on the data into a single

unit
A programming language that implements OOD is called an
object-oriented programming (OOP) language
To design and use objects, you must learn how to:
Represent data in computer memory
Manipulate data
Implement operations
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To create operations:
Write algorithms and implement them in a programming
language
Use functions to implement algorithms
Learn how to combine data and operations on the data into a
single unit called a class
C++ was designed to implement OOD
OOD is used with structured design
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ANSI/ISO Standard C++
C++ evolved from C
C++ designed by Bjarne Stroustrup at Bell Laboratories in early
1980s
Many different C++ compilers were available
C++ programs were not always portable from one compiler to
another
In mid-1998, ANSI/ISO C++ language standards were approved
Second standard, called C++11, was approved in 2011
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Quick Review (1 of 3)
A computer is an electronic device that can perform arithmetic
and logical operations
A computer system has hardware and software components
The central processing unit (CPU) is the brain
Primary storage (MM) is volatile; secondary storage (e.g., disk)
is permanent
The operating system monitors overall activity of the computer
and provides services
There are various kinds of languages

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Compiler: translates high-level language into machine code
Algorithm:
Step-by-step problem-solving process
Arrives at a solution in a finite amount of time
Problem-solving process
Analyze the problem and design an algorithm
Implement the algorithm in code
Maintain the program
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Structured design
Problem is divided into smaller subproblems
Each subproblem is solved
Combine solutions to all subproblems
Object-oriented design (OOD) program: a collection of
interacting objects
Object: data and operations on those data

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9781337117562_ppt_ch02.pptx
Chapter 2
Basic Elements of C++
classroom
Eighth Edition
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Objectives (1 of 3)
Become familiar with the basic components of a C++ program,
including functions, special symbols, and identifiers
Explore simple data types
Discover how to use arithmetic operators
Examine how a program evaluates arithmetic expressions
Become familiar with the string data type
Learn what an assignment statement is and what it does

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2
Objectives (2 of 3)
Learn about variable declaration
Discover how to input data into memory using input statements
Become familiar with the use of increment and decrement
operators
Examine ways to output results using output statements
Learn how to use preprocessor directives and why they are
necessary
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Objectives (3 of 3)
Learn how to debug syntax errors
Explore how to properly structure a program, including using
comments to document a program
Become familiar with compound statements

Learn how to write a C++ program
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Introduction
Computer program
A sequence of statements whose objective is to accomplish a
task
Programming
The process of planning and creating a program
Real-world analogy: a recipe for cooking
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A Quick Look at a C++ Program (1 of 5)

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Sample Run:
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FIGURE 2-1 Various parts of a C++ program
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FIGURE 2-1 Various parts of a C++ program (cont’d.)
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Variable: a memory location whose contents can be changed
FIGURE 2-3 Memory allocation
FIGURE 2-4 Memory spaces after the statement length = 6.0;
executes
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The Basics of a C++ Program
Subprogram (or function): collection of statements
When executed, accomplishes something
May be predefined or standard
Syntax rules: rules that specify which statements (instructions)
are legal or valid
Semantic rules: determine the meaning of the instructions
Programming language: a set of rules, symbols, and special
words
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Comments
Comments are for the reader, not the compiler
Two types
Single line: begins with //
//***************************************************
***********
// Given the length and width of a rectangle, this C++ program
// computes and outputs the perimeter and area of the rectangle.
//***************************************************
***********
Multiple line: enclosed between /* and */
/*
You can include comments that can
occupy several lines.

*/
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Special Symbols
A token is the smallest individual unit of a program written in
any language
C++ tokens include special symbols, word symbols, and
identifiers
Special symbols in C++ include:
+-*/
.;?,
<=!===>=
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Reserved Words (Keywords)
Reserved word symbols (or keywords):

Cannot be redefined within a program
Cannot be used for anything other than their intended use
Examples include:
int
float
double
char
const
void
return
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Identifiers (1 of 2)
An identifier is the name of something that appears in a
program
Consists of letters, digits, and the underscore character (_)
Must begin with a letter or underscore
C++ is case sensitive
NUMBER is not the same as number
Two predefined identifiers are cout and cin
Unlike reserved words, predefined identifiers may be redefined,
but it is not a good idea

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Identifiers (2 of 2)
Legal identifiers in C++
first
conversion
payRate
TABLE 2-1 Examples of Illegal IdentifiersIllegal
IdentifierReasonA Correct Identifieremployee SalaryThere can
be no space between
employee and Salary.employeeSalaryHello!The exclamation
mark cannot be used in an identifier.Helloone+twoThe symbol +
cannot be used in an identifier.onePlusTwo2ndAn identifier
cannot begin with a digit.second
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Whitespaces
Every C++ program contains whitespaces
Include blanks, tabs, and newline characters
Whitespaces separate special symbols, reserved words, and

identifiers
Proper utilization of whitespaces is important
Can be used to make the program more readable
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Data Types
A data type is set of values together with a set of allowed
operations
C++ data types fall into three categories:
Simple data type
Structured data type
Pointers
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Simple Data Types (1 of 2)
Three categories of simple data

Integral: integers (numbers without a decimal)
Can be further categorized: char, short, int, long, bool, unsigned
char, unsigned short, unsigned int, unsigned long
Floating-point: decimal numbers
Enumeration: a user-defined data type
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Simple Data Types (2 of 2)
Different compilers may allow different ranges of values
TABLE 2-2 Values and Memory Allocation for Simple Data
TypesData TypeValuesStorage (in bytes)int–147483648 (= –231
) to 2147483647 (= 231 – 1)4booltrue and false1char–128 (= –
27 ) to 127 (= 27 – 1)1long long–9223372036854775808 (–263 )
to
9223372036854775807(263 – 1)64
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int Data Type
Examples
-6728
0
78
+763
Positive integers do not require a + sign
A comma cannot be used within an integer
Commas are only used for separating items in a list
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bool Data Type
bool type
Two values: true and false
Purpose: to manipulate logical (Boolean) expressions
true and false
Logical values
bool, true, and false
Reserved words

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char Data Type (1 of 2)
Data type char is the smallest integral data type
It is used for single characters: letters, digits, and special
symbols
Each character is enclosed in single quotes
'A', 'a', '0', '*', '+', '$', '&'
A blank space is a character
Written ' ', with a space left between the single quotes
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char Data Type (2 of 2)
Different character data sets exist
ASCII: American Standard Code for Information Interchange
Each of 128 values in ASCII code set represents a different
character
Characters have a predefined ordering based on the ASCII
numeric value
Collating sequence: ordering of characters based on the

character set code
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Floating-Point Data Types (1 of 3)
C++ uses scientific notation to represent real numbers (floating-
point notation)
TABLE 2-3 Examples of Decimal Numbers in Scientific and
C11 Floating-Point NotationsDecimal NumberScientific
NotationC++ Floating-Point Notation75.9247.5924 *
1017.592400E10.181.8 * 10-11.800000E-10.00004534.53 * 10-
54.530000E-5–1.482-1.482 * 100-1.482000E07800.07.8 *
1037.800000E3
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float: represents any real number

Range: -3.4 * 1038 to 3.4 * 1038 (four bytes)
double: represents any real number
Range: –1.7 * 10308 to 1.7 * 10308 (eight bytes)
Minimum and maximum values of data types are system
dependent
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Maximum number of significant digits (decimal places) for float
values: 6 or 7
Maximum number of significant digits for double: 15
Precision: maximum number of significant digits
float values are called single precision
double values are called double precision
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Data Types, Variables, and Assignment Statements
To declare a variable, must specify its data type
Syntax rule to declare a variable is:
dataType identifier;
Examples include:
int counter;
double interestRate;
char grade;
Assignment statement has the form: variable = expression
Example: interestRate = 0.05;
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Arithmetic Operators, Operator Precedence, and Expressions (1
of 2)
C++ arithmetic operators include:
+ addition
- subtraction (or negation)
* multiplication
/ division
% mod (modulus or remainder)
+, -, *, and / can be used with integral and floating-point data
types
Modulus (%) can only be used with integral data types

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Arithmetic Operators, Operator Precedence, and Expressions (2
of 2)
When you use / with integral data types, the integral result is
truncated (no rounding)
Arithmetic expressions contain values and arithmetic operators
Operands are the numbers appearing in the expressions
Operators can be unary (one operand) or binary (two operands)
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Order of Precedence
All operations inside () are evaluated first
*, /, and % are at the same level of precedence and are
evaluated next
+ and - have the same level of precedence and are evaluated last
When operators are on the same level
Operations are performed from left to right (associativity)
3 * 7 - 6 + 2 * 5 / 4 + 6 means

(((3 * 7) – 6) + ((2 * 5) / 4 )) + 6
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Expressions
Integral expression: all operands are integers
Yields an integral result
Example: 2 + 3 * 5
Floating-point (decimal) expression: all operands are floating-
point
Yields a floating-point result
Example: 12.8 * 17.5 - 34.50
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Mixed Expressions (1 of 2)
Mixed expression
Has operands of different data types

Contains integers and floating-point
Examples of mixed expressions
2 + 3.5
6 / 4 + 3.9
5.4 * 2 – 13.6 + 18 / 2
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Mixed Expressions (2 of 2)
Evaluation rules
If operator has same types of operands
The operator is evaluated according to the type of the operands
If operator has both types of operands
Integer is changed to floating-point
Operator is evaluated
Result is floating-point
Entire expression is evaluated according to precedence rules
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Type Conversion (Casting) (1 of 2)
Implicit type coercion: when the value of one type is
automatically changed to another type
Cast operator (also called type conversion or type casting):
provides explicit type conversion
static_cast<dataTypeName>(expression)
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Type Conversion (Casting) (2 of 2)
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string Type
Data type string is a programmer-defined type supplied in
ANSI/ISO Standard C++ library
A string is a sequence of zero or more characters enclosed in
double quotation marks
A null (or empty) string is a string with no characters
Each character has a relative position in the string
Position of first character is 0
The length of a string is the number of characters in it
Example: length of "William Jacob" is 13
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Variables, Assignment Statements, and Input Statements
Data must be loaded into main memory before it can be
manipulated
Storing data in memory is a two-step process:
Instruct the computer to allocate memory
Include statements in the program to put data into the allocated
memory
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Allocating Memory with Constants and Variables (1 of2)
Named constant: memory location whose content cannot change
during execution
Syntax to declare a named constant
In C++, const is a reserved word
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Allocating Memory with Constants and Variables (2 of 2)
Variable: memory location whose content may change during
execution
Syntax to declare one or multiple variables

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Putting Data into Variables
Ways to place data into a variable
Use C++’s assignment statement
Use input (read) statements
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Assignment Statement (1 of 4)
The assignment statement takes the form:
Expression is evaluated and its value is assigned to the variable
on the left side
A variable is said to be initialized the first time a value is
placed into it
In C++, = is called the assignment operator

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Example 2-14 illustrates a walk-through (tracing values through
a sequence)
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Given int variables x, y, and z. How is this legal C++ statement
evaluated?
x = y = z
The assignment operator is evaluated from right to left
The associativity of the assignment operator is from right to left
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Saving and Using the Value of an Expression
Declare a variable of the appropriate data type
Assign the value of the expression to the variable that was
declared
Use the assignment statement
Wherever the value of the expression is needed, use the variable
holding the value
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Declaring and Initializing Variables
Not all types of variables are initialized automatically
Variables can be initialized when declared:
int first = 13, second = 10;
char ch = ' ';
double x = 12.6;
All variables must be initialized before they are used
But not necessarily during declaration
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Input (Read) Statement (1 of 3)
cin is used with >> to gather one or more inputs
This is called an input (read) statement
The stream extraction operator is >>
For example, if miles is a double variable:
cin >> miles;
Causes the computer to get a value of type double and places it
in the variable miles

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Using more than one variable in cin allows more than one value
to be read at a time
Example: if feet and inches are variables of type int, this
statement:
cin >> feet >> inches;
Inputs two integers from the keyboard
Places them in variables feet and inches respectively
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Increment and Decrement Operators
Increment operator (++): increase variable by 1
Pre-increment: ++variable
Post-increment: variable++
Decrement operator: (--) decrease variable by 1
Pre-decrement: --variable
Post-decrement: variable--
What is the difference between the following?
x = 5;
y = ++x;
x = 5;
y = x++;
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Output (1 of 4)

The syntax of cout and << is:
Called an output statement
The stream insertion operator is <<
Expression evaluated and its value is printed at the current
cursor position on the screen
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‹#›
52
Output (2 of 4)
A manipulator is used to format the output
Example: endl causes the insertion point to move to beginning
of next line
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‹#›
53

Output (3 of 4)
The new line character (new line escape sequence) is 'n'
May appear anywhere in the string
Examples
cout << "Hello there.";
cout << "My name is James.";
Output:
Hello there.My name is James.
cout << "Hello there.n";
cout << "My name is James.";
Output :
Hello there.
My name is James.
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‹#›
54
Output (4 of 4)
TABLE 2-4 Commonly Used Escape SequencesEscape
SequenceDescriptionnNewlineCursor moves to the beginning of
the next linetTabCursor moves to the next tab
stopbBackspaceCursor moves one space to the
leftrReturnCursor moves to the beginning of the current line
(not the next line)BackslashBackslash is printed'Single
quotationSingle quotation mark is printed"Double
quotationDouble quotation mark is printed

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55
Preprocessor Directives (1 of 2)
C++ has a small number of operations
Many functions and symbols needed to run a C++ program are
provided as collection of libraries
Every library has a name and is referred to by a header file
Preprocessor directives are processed by the preprocessor
program
All preprocessor commands begin with #
No semicolon is placed at the end of these commands
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‹#›
56
Preprocessor Directives (2 of 2)
Syntax to include a header file

For example:
#include <iostream>
Causes the preprocessor to include the header file iostream in
the program
Preprocessor commands are processed before the program goes
through the compiler
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57
namespace and Using cin and cout in a Program
cin and cout are declared in the header file iostream, but within
std namespace
To use cin and cout in a program, use the following two
statements:
#include <iostream>
using namespace std;
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‹#›

58
Using the string Data Type in a Program
To use the string type, you need to access its definition from the
header file string
Include the following preprocessor directive:
#include <string>
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59
‹#›
59
Creating a C++ Program (1 of 3)
A C++ program is a collection of functions, one of which is the
function main
The syntax of the function main used in this book has this form:
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‹#›
60
Source code is comprised of preprocessor directives and
program statements
The source code file (source file) contains the source code
The compiler generates the object code (file extension .obj)
Executable code (file extension .exe) results when object code
is linked with the system resources
The first line of the function main is called the heading of the
function:
int main()
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‹#›
61
The statements enclosed between the curly braces ({ and })
form the body of the function
A C++ program contains two types of statements:

Declaration statements declare things, such as variables
Executable statements perform calculations, manipulate data,
create output, accept input, etc.
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‹#›
62
Debugging: Understanding and Fixing Syntax Errors (1 of 2)
Sample program with line numbers added on the left
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63
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63
Debugging: Understanding and Fixing Syntax Errors (2 of 2)
Compile the program
Compiler will identify the syntax errors
The line numbers where the errors occur are specified:
ExampleCh2_Syntax_Errors.cpp
c:examplech2_syntax_errors.cpp(9): error C2146: syntax error:

missing ';' before identifier 'num'
c:examplech2_syntax_errors.cpp(11): error C2065: 'tempNum':
undeclared identifier
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64
‹#›
64
Program Style and Form: Syntax
Syntax rules indicate what is legal and what is not legal
Errors in syntax are found in compilation
int x;//Line 1
int y//Line 2
double z;//Line 3
y = w + x;//Line 4
Compilation errors would occur at:
Line 2 (missing semicolon)
Line 4 (identifier w used but not declared)
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65
Use of Blanks
In C++, you use one or more blanks to separate numbers when
data is input
Blanks are also used to separate reserved words and identifiers
from each other and from other symbols
Blanks must never appear within a reserved word or identifier
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66
‹#›
66
Use of Semicolons, Brackets, and Commas
All C++ statements end with a semicolon
Also called a statement terminator
{ and } are not C++ statements
Can be regarded as delimiters
Commas separate items in a list
Declaring more than one variable following a data type
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‹#›

67
Semantics
Semantics: set of rules that gives meaning to a language
Possible to remove all syntax errors in a program and still not
have it run
Even if it runs, it may still not do what you meant it to do
Example: 2 + 3 * 5 and (2 + 3) * 5
Both are syntactically correct expressions but have different
meanings
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68
‹#›
68
Naming Identifiers
Identifiers can be self-documenting
CENTIMETERS_PER_INCH
Avoid run-together words
annualsale
Solution

s may include:
Capitalizing the beginning of each new word: annualSale
Inserting an underscore just before a new word: annual_sale
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69
‹#›
69
Prompt Lines
Prompt lines: executable statements that inform the user what to
do
cout << "Please enter a number between 1 and 10 and "
<< "press the return key" << endl;
cin >> num;
Always include prompt lines when input is needed from users

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70
Documentation
A well-documented program is easier to understand and modify
You use comments to document programs
Comments should appear in a program to:
Explain the purpose of the program
Identify who wrote it
Explain the purpose of particular statements
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‹#›
71
Form and Style
Consider two ways of declaring variables:
Method 1
int feet, inches;
double x, y;
Method 2
int feet,inches; double x,y;
Both are correct; however, the second is harder to read
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72
‹#›
72

More on Assignment Statements
Two forms of assignment
Simple and compound
Compound operators provide more concise notation
Compound operators: +=, -=, *=, /=, %=
Simple assignment statement example
x = x * y;
Compound assignment statement example
x *= y;
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73
‹#›
73
A C++ program is a collection of functions, one of which is
always called main
Identifiers consist of letters, digits, and underscores, and begin

with a letter or an underscore
The arithmetic operators in C++ are addition (+), subtraction (-
), multiplication (*), division (/), and modulus (%)
Arithmetic expressions are evaluated using the precedence
associativity rules
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74
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74
All operands in an integral expression are integers
All operands in a floating-point expression are decimal numbers
A mixed expression contains both integers and decimal numbers
Use the cast operator to explicitly convert values from one data
type to another
A named constant is initialized when declared
All variables must be declared before used

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‹#›
75
Use cin and the stream extraction operator >> to input from the
standard input device
Use cout and the stream insertion operator << to output to the
standard output device
Preprocessor commands are processed before the program goes
through the compiler
A file containing a C++ program usually ends with the
extension .cpp

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76
‹#›
76
9781337117562_ppt_ch03.pptx
Chapter 3
Input/Output
Eighth Edition
‹#›
1
Objectives (1 of 2)

Learn what a stream is and examine input and output streams
Explore how to read data from the standard input device
Learn how to use predefined functions in a program
Explore how to use the input stream functions get, ignore,
putback, and peek
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2
‹#›
2
Objectives (2 of 2)
Become familiar with input failure
Learn how to write data to the standard output device
Discover how to use manipulators in a program to format output
Learn how to perform input and output operations with the
string data type
Learn how to debug logic errors
Become familiar with file input and output

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3
‹#›
3
I/O Streams and Standard I/O Devices (1 of 3)
I/O: sequence of bytes (stream of bytes) from source to
destination
Bytes are usually characters, unless program requires other
types of information
Stream: sequence of characters from the source to the
destination
Input stream: sequence of characters from an input device to the
computer
Output stream: sequence of characters from the computer to an
output device

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4
‹#›
4
Use iostream header file to receive data from keyboard and send
output to the screen
Contains definitions of two data types:
istream: input stream
ostream: output stream
Has two variables:
cin: stands for common input
cout: stands for common output
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5

‹#›
5
Variable declaration is similar to:
istream cin;
ostream cout;
To use cin and cout, the preprocessor directive#include
<iostream> must be used
Input stream variables: type istream
Output stream variables: type ostream
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6
‹#›
6

cin and the Extraction Operator >> (1 of 7)
The syntax of an input statement using cin and the extraction
operator >> is
The extraction operator >> is binary
Left-side operand is an input stream variable
Example: cin
Right-side operand is a variable
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7
‹#›
7
No difference between a single cin with multiple variables and
multiple cin statements with one variable in each statement

cin >> payRate >> hoursWorked;
cin >> payRate;
cin >> hoursWorked;
When scanning, >> skips all whitespace
Blanks and certain nonprintable characters
>> distinguishes between character 2 and number 2 by the right-
side operand of >>
If type char or int (or double), the 2 is treated as a character or
as a number 2, respectively
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8
‹#›
8
TABLE 3-1 Valid Input for a Variable of the Simple Data
TypeData Type of aValid Input for acharOne printable character

except the blank.intAn integer, possibly preceded by a + or -
sign.doubleA decimal number, possibly preceded by a + or -
sign. If the actual data input is an integer, the input is converted
to a decimal number with the zero decimal part.
Entering a char value into an int or double variable causes
serious errors, called input failure
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9
‹#›
9
When reading data into a char variable
>> skips leading whitespace, finds and stores only the next
character
Reading stops after a single character
To read data into an int or double variable
>> skips leading whitespace, reads + or - sign (if any), reads the

digits (including decimal for floating-point variables)
Reading stops on whitespace or a non-digit character
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10
‹#›
10
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11
‹#›

11
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12
‹#›
12
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13

‹#›
13
Using Predefined Functions in a Program (1 of 3)
A function (subprogram) is a set of instructions
When activated, it accomplishes a task
main executes when a program is run
Other functions execute only when called
C++ includes a wealth of functions
Predefined functions are organized as a collection of libraries
called header files
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14
‹#›
14

Header file may contain several functions
To use a predefined function, you need the name of the
appropriate header file
You also need to know:
Function name
Number of parameters required
Type of each parameter
What the function is going to do
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15
‹#›
15
To use pow (power), include cmath

Two numeric parameters
Syntax: pow(x,y) = xy
x and y are the arguments or parameters
In pow(2,3), the parameters are 2 and 3
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16
‹#›
16
cin and the get Function
The get function
Inputs next character (including whitespace)
Stores in memory location indicated by its argument
The syntax of cin and the get function
varChar is a char variable
It is the argument (or parameter) of the function

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17
‹#›
17
cin and the ignore Function (1 of 2)
ignore function
Discards a portion of the input
The syntax to use the function ignore is:
intExp is an integer expression
chExp is a char expression
If intExp is a value m, the statement says to ignore the next m
characters or all characters until the character specified by
chExp

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18
‹#›
18
cin and the ignore Function (2 of 2)
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19
‹#›
19

The putback and peek Functions (1 of 2)
putback function
Places previous character extracted by the get function from an
input stream back to that stream
peek function
Returns next character from the input stream
Does not remove the character from that stream
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20
‹#›
20
The putback and peek Functions (2 of 2)
Syntax for putback
istreamVar: an input stream variable (such as cin)
ch is a char variable
Syntax for peek

istreamVar: an input stream variable (such as cin)
ch is a char variable
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21
‹#›
21
The Dot Notation between I/O Stream Variables and I/O
Functions: A Precaution
In the statement
cin.get(ch);
cin and get are two separate identifiers separated by a dot
Called the dot notation, the dot separates the input stream
variable name from the member, or function, name

In C++, the dot is the member access operator
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22
‹#›
22
Input Failure
Things can go wrong during execution
If input data does not match corresponding variables, the
program may run into problems
Trying to read a letter into an int or double variable will result
in an input failure
If an error occurs when reading data
Input stream enters the fail state

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23
‹#›
23
The clear Function
Once in a fail state, all further I/O statements using that stream
are ignored
The program continues to execute with whatever values are
stored in variables
This causes incorrect results
The clear function restores the input stream to a working state
The syntax of the function clear is:
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24
‹#›

24
Output and Formatting Output
Syntax of cout when used with <<
expression is evaluated
value is printed
manipulator is used to format the output
Example: endl
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25
‹#›
25
setprecision Manipulator

Syntax
Outputs decimal numbers with up to n decimal places
Must include the header file iomanip
#include <iomanip>
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26
‹#›
26
fixed Manipulator
fixed outputs floating-point numbers in a fixed decimal format
Example: cout << fixed;
Disable by using the stream member function unsetf
Example: cout.unsetf(ios::fixed);
scientific manipulator outputs floating-point numbers in
scientific format

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27
‹#›
27
showpoint Manipulator
showpoint forces output to show the decimal point and trailing
zeros
Examples
cout << showpoint;
cout << fixed << showpoint;
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28

‹#›
28
C++14 Digit Separator
Reading and writing of long numbers can be error prone
In C++, commas cannot be used to separate the digits of a
number
C++14 introduces digit separator ' (single-quote character)
Example: 87523872918 can be represented as 87'523'872'918
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29
‹#›
29
setw

Outputs the value of an expression in a specified number of
columns
cout << setw(5) << x << endl;
If number of columns exceeds the number of columns required
by the expression
Output of the expression is right-justified
Unused columns to the left are filled with spaces
Must include the header file iomanip
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30
‹#›
30
Additional Output Formatting Tools
Additional formatting tools that give you more control over
your output:
setfill manipulator
left and right manipulators

unsetf manipulator
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31
‹#›
31
setfill Manipulator
Output stream variables can use setfill to fill unused columns
with a character
Example:
cout << setfill('#');

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32
‹#›
32
left and right Manipulators
left manipulator left-justifies the output
Disable left by using unsetf
right manipulator right-justifies the output
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33
‹#›

33
Types of Manipulators
Two types of manipulators
Those with parameters
Those without parameters
Parameterized stream manipulators require the iomanip header
setprecision, setw, and setfill
Manipulators without parameters require the iostream header
endl, fixed, scientific, showpoint, and left
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34
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34
Input/Output and the string Type
An input stream variable (such as cin) and >> operator can read

a string into a variable of the data type string
The extraction operator:
Skips any leading whitespace characters
Stops reading at a whitespace character
The function getline reads until end of the current line
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35
‹#›
35
Debugging: Understanding Logic Errors and Debugging with
cout statements
Syntax errors are reported by the compiler
Logic errors are typically not caught by the compiler
Spot and correct using cout statements
Temporarily insert an output statement
Correct the problem

Remove output statement
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36
File Input/Output
A file is an area in secondary storage to hold info
File I/O is a five-step process
Include fstream header
Declare file stream variables
Associate the file stream variables with the input/output sources
– referred to as opening the files
Use the file stream variables with >>, <<, or other input/output
functions
Close the files

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37
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37
Stream: infinite sequence of characters from a source to a
destination
Input stream: from a source to a computer
Output stream: from a computer to a destination
cin: common input
cout: common output
To use cin and cout, include iostream header
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‹#›
38
get reads data character-by-character
ignore skips data in a line
putback puts last character retrieved by get back to the input
stream
peek returns next character from input stream, but does not
remove it
Attempting to read invalid data into a variable causes the input
stream to enter the fail state
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39
‹#›
39

The manipulators setprecision, fixed, showpoint, setw, setfill,
left, and right can be used for formatting output
Include iomanip for the manipulators setprecision, setw, and
setfill
Header fstream contains the definitions of ifstream and ofstream
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40
‹#›
40
9781337117562_ppt_ch04.pptx
Chapter 4
Control Structures I (Selection)

Eighth Edition
‹#›
1
Objectives (1 of 2)
Learn about control structures
Examine relational operators
Discover how to use the selection control structures if, if…else
Examine int and bool data types and logical (Boolean)
expressions
Examine logical operators
Explore how to form and evaluate logical (Boolean) expressions
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‹#›

2
Objectives (2 of 2)
Learn how relational operators work with the string type
Become aware of short-circuit evaluation
Learn how the conditional operator, ?:, works
Learn how to use pseudocode to develop, test, and debug a
program
Discover how to use a switch statement in a program
Learn how to avoid bugs by avoiding partially understood
concepts
Learn how to use the assert function to terminate a program
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‹#›
3

Control Structures (1 of 2)
A computer can proceed:
In sequence
Selectively (branch): making a choice
Repetitively: looping
By calling a function
The two most common control structures are:
Selection
Repetition
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‹#›
4
Control Structures (2 of 2)
FIGURE 4-1 Flow of execution

classroom
‹#›
5
Selection: if and if...else
An expression that evaluates to true or false is called a logical
expression
“8 is greater than 3” is true
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‹#›
6
Relational Operators

TABLE 4-1 Relational Operators in
C++OperatorDescription==equal to!=not equal to<less
than<=less than or equal to>greater than>=greater than or equal
to
Each relational operator is a binary operator (requires two
operands)
Expressions using these operators always evaluate to true or
false
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‹#›
Relational Operators and Simple Data Types
You can use the relational operators with all three simple data
types
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‹#›
8
Comparing Characters
In an expression of char values using relational operators:
The result depends on the machine’s collating sequence
ASCII character set
Logical (Boolean) expressions:
Include expressions such as 4 < 6 and 'R' > 'T’
Return an integer value of 1 if the logical expression evaluates
to true
Return an integer value of 0 otherwise
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‹#›
9

One-Way Selection (1 of 2)
One-way selection syntax
The statement is:
Executed if the value of the expression is true
Bypassed if the value is false; program goes to the next
statement
The expression is also called a decision maker
The statement following the expression is also called the action
statement
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‹#›
10
One-Way Selection (2 of 2)

FIGURE 4-2 One-way selection
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‹#›
11
Two-Way Selection (1 of 2)
Two-way selection syntax
If expression is true, statement1 is executed; otherwise,
statement2 is executed
statement1 and statement2 are any C++ statements
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‹#›
12
Two-Way Selection (2 of 2)
FIGURE 4-3 Two-way selection
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‹#›
13
int Data Type and Logical (Boolean) Expressions
Earlier versions of C++ did not provide built-in data types that
had Boolean values
Logical expressions evaluate to either 1 or 0
Logical expression value was stored in a variable of the data
type int

You can use the int data type to manipulate logical (Boolean)
expressions
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‹#›
14
bool Data Type and Logical (Boolean) Expressions
The data type bool has logical (Boolean) values true and false
bool, true, and false are reserved words
The identifier true has the value 1
The identifier false has the value 0

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‹#›
15
Logical (Boolean) Operators and Logical Expressions (1 of 5)
Logical (Boolean) operators enable you to combine logical
expressions
TABLE 4-2 Logical (Boolean) Operators in
C++OperatorDescription!not&&and||or
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‹#›
16
TABLE 4-3 The ! (Not) OperatorExpression!(Expression)true

(nonzero)false (0)false (0)true (1)
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‹#›
17
TABLE 4-4 The && (And)
OperatorExpression1Expression2Expression1 &&
Expression2true (nonzero)true (nonzero)true (1)true
(nonzero)false (0)false (0)false (0)true (nonzero)false (0)false
(0)false (0)false (0)
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18
TABLE 4-5 The || (Or)
OperatorExpression1Expression2Expression1 || Expression2true
(nonzero)true (nonzero)true (1)true (nonzero)false (0)true
(1)false (0)true (nonzero)true (1)false (0)false (0)false (0)
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‹#›
19

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‹#›
Order of Precedence (1 of 5)
Relational and logical operators are evaluated from left to right
The associativity is left to right
Parentheses can override precedence
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21
TABLE 4-6 Precedence of OperatorsOperatorsPrecedence!, +, -
(unary operators)first*, /, %second+, -third<, <=, >=,

>fourth==, !=fifth&&sixth||seventh= (assignment operator)last
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‹#›
22
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‹#›
23

9781337117562_ppt_ch01.pptxChapter 1An Overview of Compute.docx

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