Sum the same index elements of two arrays and store the result in different array

Sum the same index elements of two arrays and store the result in different array.

For example:

If the input arrays are 

1 2 3 4  5
6 7 8 9 10

then the resultant array is
7 9 11 13 15

Implementation:

#include <stdio.h>

int main(void) {
 int *a,*b,*sum,i,n;
 
 /* Get the number of elements of the array */
 scanf("%d",&n);
 
 /* allocate the memory for array a and array b */
 a=(int*)malloc(sizeof(int)*n);
 b=(int*)malloc(sizeof(int)*n);
 
 /* allocate the memory for array sum and initialize their values to zero */
 sum=(int*)calloc(n,sizeof(int));
 
 /* Get the elements of the array a */
 for(i=0;i<n;i++)
  scanf("%d",(a+i));
  
 /* Get the elements of the array b */
 for(i=0;i<n;i++)
  scanf("%d",(b+i));
 
 /* Sum the same indexed array a and array b & store the result in array sum */
 for(i=0;i<n;i++)
  *(sum+i)=*(a+i)+*(b+i);
 
 /* print the array sum , which has the sum of array a and array b */
 for(i=0;i<n;i++)
  printf("%d ",*(sum+i));
  
 return 0;
}