CSEG1001Unit 2 C Programming Fundamentals

CSEG 1001
Computer Programming
Instructor
Dhiviya Rose J . Asst. Prof. Senior Scale
School of Computer Science and Engineering | UPES
CSEG1001 Computer Programming

Road Map
• Generations of Computers and Languages
• Organization of Computers-Online Lecture
• Number Systems Conversion
• Logical Analysis and Thinking
Introduction to
Computers
• Structure of C Program & Compilation and Linking Process
• Variables and Datatypes
• Managing Input and Output statements and Operators
• Decision and Looping Statements
C Programming
Basics
• Creation and Usages
• 1D and 2 D arrys
• String Functions
• Matrix operations
Arrays and
Strings
• Declaration and Definitions of Functions
• Passing Arguments
• Recursion
• Pointers & Pointer Arithmetic
Functions and
Pointers
• Need of Structure and Unions
• Declaration and Definition
• Storage classes
• Preprocessor Directives
Structures and
Unions

LECTURE #8
STRUCTURE OF C PROGRAM ..COMPILATIONAND
LINKING
Instructor

Steps in C compilation
• Compiling a C program is a multi-stage process
• It contains four separate stages:
• Traditional C compilers orchestrate this process by
invoking other programs to handle each stage.
Preprocessing Compilation Assembly Linking

Compiling and Executing C Program

Files in a C program

Structure
of
C
Program

Documentation
• Comments
• provide clarity to the C source code
• allows others to better understand
• helps in debugging the code.
• Two types
• Single Line //
• Multiline /* any text */

Hello World in C
// This is my first Program
/* Written for Engineering students of
Petroleum University */
#include <stdio.h>
void main()
{
printf(“Hello”);
}
11
Instructor: Dhiviya Rose J , AP-Sr. Scale | CIT

Preprocessing
• First stage of compilation
• Lines starting with a # character are interpreted by the
preprocessor as preprocessor commands.
• This language is used to reduce repetition in source code
• Print the result of the preprocessing stage, pass the -E
option to cc:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

Function / Block
• Definition: Function/Procedure/Sub-routine
• Set of Instructions that are executed to achieve a particular task
• Code reusability
• Types
• Built-in Functions (System Defined)
• E.g. printf(), scanf()
• User-defined Functions
13

Main() function
 main() is always the first function called in a program
execution.
void main( void ) or int main()
{ … {….
 void indicates that the function takes no arguments
 int indicates that the function returns an integer value

LECTURE #9
VARIABLESAND DATATYPES
Instructor

Data & Variable

DataType in C language

Variables
• Naming a Variable
• Must be a valid identifier.
• Must not be a keyword
• Names are case sensitive.
• Variables are identified by only first 32 characters.
• length
• lowerLimit lower_limit
• incomeTax income_tax

Variable Declaration / Definition
• Declaring/Definition a Variable
• Declaration announces the data type of a variable and allocates
appropriate memory location.
• Each variable used must be declared.
• A form of a declaration statement is
data-type var1, var2,…;
Examples
int sum = 0;
char t1 = ‘a’;
float epsilon = 1.44;

Variable Definition and Initialization
If not initialized it will take a garbage value.

22
Global and Local Variables
• Global Variables
• These variables are
declared outside all
functions.
• Life time of a global
variable is the entire
execution period of the
program.
• Can be accessed by any
function defined below the
declaration, in a file.
• Local Variables
• These variables are
declared inside some
functions.
• Life time of a local
variable is the entire
execution period of the
function in which it is
defined.
• Cannot be accessed by any
other function.
• In general variables
declared inside a block are
accessible only in that
block.

Constants
• The value will not change wherever declared
• Declared using const keyword
• Eg.
const float pi=3.14;

LECTURE #10
INPUTAND OUTPUT STATEMENTS
Instructor

OUTPUT STATEMENT - printf()
• printf() function
• Output to Standard Output
• Prototype definition available in stdio.h
26

• Case 1: printing only text
Flowchart code Output
printf(“Hello”); Hello
• Case 2: printing only value of a variable
printf(“%d” , area); 120
• Case 3: printing text and a value
printf(“The value of area is %d”,area); The value of area is 120
Print Hello
Print area
OUTPUT STATEMENT - printf()

INPUT STATEMENT – scanf()
• Case 1: getting 1 input value
scanf( “%d”, &r);
scanf( “%d %d ”, &l, &b);
scanf( “%d %d %d ”, &a, &b ,&c);

• scanf() function
• Input from Standard Input
• Prototype definition available in stdio.h
• Format Specifier(%d)
• Address-of Operator (&)
• Provides the memory address of the input variable were the input value is to
be stored
29

Format Specifiers in C
• Used in association with printf() and scanf()

ONLINE LECTURE #11
OPERATORS IN C
Instructor

Online lectures

Ternary Operator - Conditional Check
Operator

Example

LECTURE #12
DECISION STRUCTURES IN C
Instructor

List of Decision Making Structures in C
•If structure
•If Else structure
•Nested If structure
•Switch Structures
•Conditional Operator/
Terniary operator

Converting a if block to C program
if(condition)
{
//true statements
}

Check if entered number is positive

Converting a if-else block to C program
if(condition)
{
//true statements
}
else
{
//false statements
}

Example: If Else Statement

Nested IF
if(condition 1)
{
//true statements
}
else if(condition 2)
{
//statements
}
else if(condition 3)
{
//statements
}
else
{
//statements
}

Switch case Vs Nested IF

Convert Switch to C program

Knowledge Checks
#include <stdio.h>
void solveMeFirst( )
{
int num1,num2;
scanf("%d %d",&num1,&num2);
int sum;
sum = num1+num2;
printf("%d",sum);
}
void main()
{
________________Fill me
}

Knowledge Checks

EXPERIMENT NO – 4
Control Statements in C Language
List of lab works:
1. Write a program to accept 3 numbers and find the greatest of them, using
if…….else statements.
2. Write a program to find the biggest of 3 numbers using conditional operator/ternary
operator?
3. Write a program to check whether the roots of a quadratic equation are real or
imaginary?
4. Program to find the average of students marks, if average<50 then result is ‘FAIL’
otherwise print the grade as pass /first class/distinction.
5. A book and stationary store decides to give its customers 10% discount on a
purchase greater than 10,000/-. The program should accept the quantity
purchased the price of the items and then calculate the amount payable. Further
based on the total amount, appropriate discount should be given and final payable
amount should be displayed.
6. Write a program to accept a number and display “Sunday/Monday/Tuesday…..”
Based on the number. (hint: if 1 is input then “Sunday”, if 2 is input then
“Monday”…..) using switch case.
7. Read the minutes from the keyboard and find out the no. of hours, mins , days ?
(Ex 1210 mins are displayed as 0 days,20 hrs,10 min)

LECTURE #13
LOOP STRUCTURES IN C
Instructor

Introduction - Loop Statements
• Helps in executing a statement in flowchart repeatedly
• Loop statements – block of statement executed more
than one time
• How many times the loop statements are executed is
managed by a counter variable
• Counter Variable Initialization
• Eg. C=0
• Counter Variable Increment/Decrement
• Eg. C++, c=c+1,c=c+3
• Counter Variable Condition Check
• Eg. C<3

List of Loop Structures in C
• While
• Do….While
• For

While
• Entry condition check loop

Example – While Program

Do … While Loop
• Exit check Loop
• At least executes the
statement once
if the condition is false

At least executes once - if condition fails

For

Continue statement

EXPERIMENT NO – 5
Loop Statements in C Language
List of lab works:
1. Write a program to print half pyramid using *.
2. Write a C program to print all natural numbers from 1-n
using while loop.
3. Write a C program to find the sum of all even numbers
between 1 to n using do-while loop.
4. Write a C program to print multiplication table of any
number using for loop.

CSEG1001Unit 2 C Programming Fundamentals

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