Question

What is recursion? WAP using recursion to find the sum of array elements of size n.

Answer 1

1. Recursion: A function that calls itself is called as recursive function and this technique is called as recursion.
2. A recursive function must definitely have a condition that exits from calling the function again.
3. Hence there must be a condition that calls the function itself if that condition is true.
4. If the condition is false then it will exit from the loop of calling itself again.

Program:
#include<conio.h>
#include <stdio.h>
#define MAX_SIZE 100
int sum(int arr[], int start, int len);
void main()
{
int arr[MAX_SIZE];
int N, i, sumof_array;
clrscr();
printf("Enter size of the array: ");
scanf("%d", &N);
printf("Enter elements in the array: ");
for(i=0; i<N; i++)
{
scanf("%d", &arr[i]);
}
sumof_array = sum(arr, 0, N);
printf("Sum of array elements: %d", sumof_array);
getch();
}
int sum(int arr[], int start, int len)
{
if(start >= len)
return 0;
return (arr[start] + sum(arr, start + 1, len));
}
Output:
Enter size of the array: 10
Enter elements in the array: 1 2 3 4 5 6 7 8 9 10
Sum of array Elements: 55