Subject : Structured Programming Approach

Title : Functions and Parameter

Difficulty : Medium

Recursion:

• A function that calls itself is called as recursive function and this technique is called as recursion.
• A recursive function must definitely have a condition that exits from calling the function again.
• Hence there must be a condition that calls the function itself if that condition is true.
• 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