This document summarizes key concepts from Lab 2 of CS106 including data types in C++, variable declaration and initialization, character escapes, strings, literals, and constants. It provides an overview of different data types like int, char, float and their typical ranges. It also demonstrates how to declare and initialize variables, use character escapes in strings, initialize and manipulate strings, examples of literals, and how to define constants in C++. The document is presented by TA Nada Kamel and provides code examples for clarification.

1. Lab 2
CS106 - Fundamentals of Computer Science
Presented by TA. Nada Kamel

2. Agenda
 Data types
 Variables declaration
 Character escapes
 Strings
 Literals
 Constants
Presented by TA. Nada Kamel

3. Data Types
Presented by TA. Nada Kamel

4. Data Types
Data Type C++ Keyword Byte(s) Typical range
Integer int 4 -2,147,483,648 to
2,147,483,647
Unsigned integer unsigned int 4 0 to 4,294,967,295
Long integer long 8 ~ -9 Billion to ~ 9 Billion
Floating point float 4 +/- 3.4e +/- 38 (~7 digits)
Double floating point double 8 +/- 1.7e +/- 308 (~15 digits)
Character char 1 128 to 127 or 0 to 255
String/Text string ∞ -
Presented by TA. Nada Kamel

5. Data Types (Cont.)
 Boolean  bool
 Void  void
Presented by TA. Nada Kamel

6. Variable Declaration
Presented by TA. Nada Kamel

7. Variable Declaration
 C++ requires every variable to be declared with its type BEFORE its first
use.
 Examples:
int height;
char letter;
float radius, diameter;
 In these examples, variables have an undetermined value.
Presented by TA. Nada Kamel

8. Variable Initialization
 Allows variable to have a specific value from the moment it is declared.
 Example:
int depth = 67;
(data type) (identifier) = initial_value;
Presented by TA. Nada Kamel

9. Character Escapes
Presented by TA. Nada Kamel

10. Character Escapes
Keyword Meaning
n or endl newline
r carriage return
t tab
v vertical tab
b backspace
a alert (beep sound)
’ single quote
” double quote
? question mark
backslash
Presented by TA. Nada Kamel

11. Strings
Presented by TA. Nada Kamel

12. Strings
 Strings are able to store sequences of characters.
 To utilize strings we must include a directive
#include <string>
 Can be initialized with any of the three valid initialization formats:
string mystring = “Hello World!”;
string mystring(“Hello World!”);
string mystring {“Hello World!”};
Presented by TA. Nada Kamel

13. Strings (Cont.)
 To input a string you will need to use:
getline(cin, mystring);
 If the user will enter one word only, cin >> mystring can be used.
 Example:
#include <iostream>
#include <string>
void main()
{
string mystring;
getline(cin, mystring);
std:: cout << “The string entered is ” << mystring << endl;
}
Presented by TA. Nada Kamel

14. Literals
Presented by TA. Nada Kamel

15. Literals
 Used to express particular values.
 Literal constants can be classified into: integers, floating-point, character,
string, boolean.
 Examples:
707
-20589
3.14
1.6e-19
‘z’
“Hello World!”
true
Presented by TA. Nada Kamel

16. Typed Constants
Presented by TA. Nada Kamel

17. Constants
 Can be used to give names to constant values.
 Example:
const float pi = 3.14159;
 The value of the constant variable cannot be changed after being
initialized.
Presented by TA. Nada Kamel

18. Any Questions?
Presented by TA. Nada Kamel