Pointers have many but easy concepts and they are very important to C programming.
Two of the arithmetic pointer concepts are explained below, which are C pointer addition and subtraction respectively.
C pointer addition
C pointer addition refers to adding a value to the pointer variable.
The formula is as follows −
new_address= current_address + (number * size_of(data type))
Example
Following is the C program for C pointer addition −
#include<stdio.h>
int main(){
int num=500;
int *ptr;//pointer to int
ptr=#//stores the address of number variable
printf("add of ptr is %u \n",ptr);
ptr=ptr+7; //adding 7 to pointer variable
printf("after adding add of ptr is %u \n",ptr);
return 0;
}Output
When the above program is executed, it produces the following result −
add of ptr is 6422036 after adding add of ptr is 6422064
C pointer subtraction
It subtracts a value from the pointer variable. Subtracting any number from a pointer variable will give an address.
The formula is as follows −
new_address= current_address - (number * size_of(data type))
Example
Following is the C program for C pointer subtraction −
#include<stdio.h>
int main(){
int num=500;
int *ptr;//pointer to int
ptr=#//stores the address of number variable
printf("addr of ptr is %u \n",ptr);
ptr=ptr-5; //subtract 5 to pointer variable
printf("after sub Addr of ptr is %u \n",ptr);
return 0;
}Output
When the above program is executed, it produces the following result −
addr of ptr is 6422036 after sub Addr of ptr is 6422016