Variables:
- Variable is an Identity given to memory location.
- Variable is used to store information.
- We need to specify the datatype of every variable.
| Syntax: datatype identifier = value; Examples: char name[] = “amar”; int age = 23; char* mail = “amar786@gmail.com”; char gender = ‘M’; double salary = 35000; |
Note: Value of a variable will change. For example “age of a person”
Variable Declaration, Assignment, Modify and Initialization:
Declaration:
- Creating a variable without value.
- For example
- int a ;
Assignment:
- Assigning a value to the variable which is already declared.
- For example,
- int a ; // declaration
- a=10 ; // assignment
Modify:
- Increase or decrease the value of a variable
- For example,
- int a ; // declaration
- a=10 ; // assignment
- a=a+20; //modify
Initialization:
- Defining a variable along with value
- For example,
- int a = 10 ; // initialization
- a = a+20 ; // modify
Rules to create variable:
- Variable contains alphabets(A-Z , a-z) or Digits (0-9) and only one symbol( _ ).
- Variable should not starts with digit
- int 5a = 10; (error)
- int a5 = 10;
- int 1stRank; (error)
- Variable should not contain spaces. 8355832471
- int acc num = 1001; (error)
- int acc_num = 1001;
- Variable should not allow other symbols except _
- int acc_num ;
- int acc-num;
- variable can starts with special symbol _
- int _acc_num;
- int _1rank;
- Variable should not match with keywords.
- int if = 10 ;
- int else = 20 ;
Variables classified into:
- Local variables:
- Defining a variable inside the block or function.
- We cannot access local variables outside to the block.
- Global variables:
- Defining a variable outside to all functions.
- We can access global variable from all functions.
Note: We will discuss briefly about Local and Global variables after Functions concept