Pointer Arithmatics : Incrementing Pointer Variable in C

Note : Incrementing Pointer is generally used in array because we have contiguous memory in array and we know the contents of next memory location.

Incrementing pointer : Incrementing Pointer Variable Depends Upon -

• data type of the Pointer variable

Formula : ( After incrementing )

new value =  current address +  i * size_of(data type)

Three Rules should be used to increment pointer -

Address + 1 = Address
Address++   = Address
++Address   = Address

Pictorial Representation :

Explanation : Incremeting Pointer

• Incrementing a pointer to an integer data will cause its value to be incremented by 2 .
• This differs from compiler to compiler as memory required to store integer vary compiler to compiler

Note to Remember

Live Example 1 : Increment Integer Pointer

#include<stdio.h>
int main(){
int *ptr=(int *)1000;
ptr=ptr+1;
printf("New Value of ptr : %u",ptr);
return 0;
}

Output :

New Value of ptr : 1002

Live Example 2 : Increment Double Pointer

#include<stdio.h>
int main(){
double *ptr=(double *)1000;
ptr=ptr+1;
printf("New Value of ptr : %u",ptr);
return 0;
}

Output :

New Value of ptr : 1004

Live Example 3 : Array of Pointer

#include<stdio.h>
int main(){
float var[5]={1.1f,2.2f,3.3f};
float(*ptr)[5];
ptr=&var;
printf("Value inside ptr : %u",ptr);
ptr=ptr+1;
printf("Value inside ptr : %u",ptr);
return 0;
}

Output :

Value inside ptr : 1000
Value inside ptr : 1020

Explanation :

   Address of ptr[0] = 1000

We are storing Address of float array to ptr[0]. -

Address of ptr[1]
= Address of ptr[0] + (Size of Data Type)*(Size of Array)
= 1000 + (4 bytes) * (5)
= 1020

Address of Var[0]…Var[4] :

   Address of var[0] = 1000
   Address of var[1] = 1004
   Address of var[2] = 1008
   Address of var[3] = 1012
   Address of var[4] = 1016

You may like this

• Incrementing Pointer
• Decrementing Pointer
• Adding number to Pointer
• Subtracting number from pointer
• Differencing
• Comparing two pointers
• Illegal Arithmetic Operations that should be avoided while using Pointer

External Link from Wikipedia