Question

Programming language C

Please go through this carefully. Needs function void add(int *a1, int n, int *a2)

Write a program addition.c that reads in an array (a1) of numbers, and creates a new array (a2) of numbers such that the first and last numbers of a1 are added and stored as the first number, the second and second-to-last numbers are added and stored as the second number, and so on.

You need to check for even and odd length of arrays. In case of an odd number of integers, leave the central integer in the original list as it is.

As part of the solution, write and call the function add() with the following prototype. The add function should add the numbers of a1 as described above.

void add(int *a1, int n, int *a2);

The add() function should use pointer arithmetic – not subscripting – to visit array elements. In other words, eliminate the loop index variables and all use of the [] operator in the function.

In the main function, ask the user to enter the length of the array, declare the array with the length, call the add function, and display the output array.

Example input/output #1: Enter the length of the array: 5 Enter the elements of the array: 8 4 1 3 9 Output: 17 7 1

Example input/output #2: Enter the length of the array: 4 Enter the elements of the array: 3 4 1 7 Output: 10 5

Answer 1

Source code:

#include<stdio.h>
#include<stdlib.h>
void add(int *a1,int n,int *a2)
{
   int i,j,k=0;
   if(n%2==0)
   {
       for(i=0,j=n-1;i<j;i++,j--)
       {
           *(a2+k)=*(a1+i)+*(a1+j);
           k++;
       }
   }
   else
   {
       for(i=0,j=n-1;i!=j;i++,j--)
       {
           *(a2+k)=*(a1+i)+*(a1+j);
           k++;
       }
       *(a2+k)=*(a1+i);
       k++;
   }
}
main()
{
   int *a1,*a2,n,i;
   printf("Enter the total array elements of a1: ");
   scanf("%d",&n);
   a1=(int*)malloc(sizeof(int)*n);
   if(n%2==0)
       a2=(int*)malloc(sizeof(int)*(n/2));
   else
       a2=(int*)malloc(sizeof(int)*(n/2+1));
   for(i=0;i<n;i++)
   {
       printf("Enter element %d: ",(i+1));
       scanf("%d",(a1+i));
   }
   add(a1,n,a2);
   printf("\nArray 1 elements are: ");
   for(i=0;i<n;i++)
   {
       printf("%d ",*(a1+i));
   }
   printf("\nArray 2 elements are: ");
   if(n%2==0)
   {
       for(i=0;i<n/2;i++)
       {
           printf("%d ",*(a2+i));
       }
   }
   else
   {
       for(i=0;i<=n/2;i++)
       {
           printf("%d ",*(a2+i));
       }
   }
}

Output: