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Introduction to pointer
Pointer is used to reference a memory location.
Pointer variable in C be used to store address of other variable.
Different properties of variable are:
1. Name:
A variable must have a name. It must follow rules of valid identifier in C.
2. Value of variable:
Variable should be assigned some value.
3. Memory location:
Each variable gets stored in a memory location that is represented as a hexadecimal number.
Pointer Operations
There are two pointer operators. They are:
i. Indirection Operator
Indirection operator is represented as * . It is used to declare a pointer variable or to refer to the value referenced by pointer variable.
Example: int *x;
ii. Address Operator
Address operator is represented as &. It is used to get a variable’s memory location .
Example:
int x=10,*y;
y=&x;
NULL Pointer
NULL refers to pointer variable not having address stored in it.
Access address
We can determine the address of a variable with the help of address operator (&).
Example:
int a=10,*b;
b=&a;
Accessing value
We can access value of a pointer variable using indirection operator.
Example:
int x=20,*y,z;
y=&x; /* y contains the address of variable x*/
z=*y; /* *y contains the value of variable x whose address is contained in pointer variable y*/
| Program |
| #include<stdio.h> int main() { int a=20,*b; b=&a; printf(“\n%d”,a); /*15*/ printf(“\n%u”,&a); /*65524*/ printf(“\n%u”,b); /*65524*/ printf(“\n%d”,*b); /*15*/ return (0); } |
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