Write a ‘C’ Program to compute the sum of all elements stored in an array using pointers

C Program to compute sum of the array elements using pointers

Program :

#include <stdio.h>
#include <conio.h>
void main() {
   int numArray[10];
   int i, sum = 0;
   int *ptr;
 
   printf("\nEnter 10 elements : ");
 
   for (i = 0; i < 10; i++)
      scanf("%d", &numArray[i]);
 
   ptr = numArray; /* a=&a[0] */
 
   for (i = 0; i < 10; i++) {
      sum = sum + *ptr;
      ptr++;
   }
 
   printf("The sum of array elements : %d", sum);
}

Output :

Enter 10 elements : 11 12 13 14 15 16 17 18 19 20
The sum of array elements is 155

Explanation of Program :

Accept the 10 elements from the user in the array.

for (i = 0; i < 10; i++)
scanf("%d", &numArray[i]);

We are storing the address of the array into the pointer.

ptr = numArray; /* a=&a[0] */

Now in the for loop we are fetching the value from the location pointer by pointer variable. Using De-referencing pointer we are able to get the value at address.

for (i = 0; i < 10; i++) {
sum = sum + *ptr;
ptr++;
}

Suppose we have 2000 as starting address of the array. Then in the first loop we are fetching the value at 2000. i.e

sum = sum + (value at 2000)
    = 0   + 11
    = 11

In the Second iteration we will have following calculation –

sum = sum + (value at 2002)
    = 11  + 12
    = 23