Write a C Program to Find sum of proper divisors of number using Recursion

By | 24.03.2017

C Program to Find sum of proper divisors of number 


Write a C Program to Find sum of proper divisors of natural number using Recursion. Here’s simple Program to Find sum of proper divisors of natural number using Recursion in C Programming Language.


Recursion : :


  • Recursion is the process of repeating items in a self-similar way. In programming languages, if a program allows you to call a function inside the same function, then it is called a recursive call of the function.
  • The C programming language supports recursion, i.e., a function to call itself. But while using recursion, programmers need to be careful to define an exit condition from the function, otherwise it will go into an infinite loop.
  • Recursive functions are very useful to solve many mathematical problems, such as calculating the factorial of a number, generating Fibonacci series, etc.

Problem : :


Given a natural number, calculate sum of all its proper divisors. A proper divisor of a natural number is the divisor that is strictly less than the number.

For example, number 20 has 5 proper divisors: 1, 2, 4, 5, 10, and the divisor summation is: 1 + 2 + 4 + 5 + 10 = 22.

Examples:

Input : n = 10
Output: 8
// proper divisors 1 + 2 + 5 = 8
Input : n = 36
Output: 55
// proper divisors 1 + 2 + 3 + 4 + 6 + 9 + 12 + 18 = 55


Below is the source code for C Program to Find sum of proper divisors of natural number using Recursion which is successfully compiled and run on Windows System to produce desired output as shown below :


SOURCE CODE : :


/* Find sum of those proper divisors of number a*/


#include<stdio.h>
int sumdiv(int num, int x);

int main()
{
        int num;
        printf("Enter a number : ");
        scanf("%d",&num);
        printf("\n\nSum of divisors = %d\n",sumdiv(num,num/2));\

        return 0;
}

sumdiv(int num, int x)
{
        if(x==1)
        {
                printf("%d  \n",x);
                return 1;
        }
        if(num%x==0)/*if x is a proper divisor*/
        {
                printf("%d + ",x);
                return x + sumdiv(num,x-1);
        }
        else
                return sumdiv(num,x-1);
}

OUTPUT  : :


************* OUTPUT **************


************* FIRST RUN ***********

Enter a number : 100
50 + 25 + 20 + 10 + 5 + 4 + 2 + 1


Sum of divisors = 117


************* SECOND RUN ***********

Enter a number : 496
248 + 124 + 62 + 31 + 16 + 8 + 4 + 2 + 1


Sum of divisors = 496

If you found any error or any queries related to the above program or any questions or reviews , you wanna to ask from us ,you may Contact Us through our contact Page or you can also comment below in the comment section.We will try our best to reach upto you in the short interval.


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Category: C Programming Recursion Programs Tags:

About Tunde A

My name is Tunde Ajetomobi, a Tech Enthusiast and Growth Hacker. I enjoy creating helpful content that solves problem across different topics. Codezclub is my way of helping young aspiring programmers and students to hone their skills and find solutions on fundamental programming languages.

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