Table of Contents
Sum of Natural Numbers Program using Recursion
C Program to find Sum of Natural Numbers using Recursion is discussed here in this tutorial.
Algorithm
Step 1 – First we declared a function sum( ) to calculate the sum of N natural numbers which accept a parameter K here K represent to the number up to which we have to find the sum.
Step 2 – Declare variable num to accept the input from user.
Step 3 – Declare variable result to store the vale of sum return by the sum() function.
Step 4 – Define the body of function sum( ) in which return statement (k +sum(k-1)) is a recursive call to sum().
Step 5 – When sum() function is called inside main() function then program control will transfer to body of sum() and sum() function will be execute and sum to number from 1 to k will be performed and return by function which will be stored in result variable.
Step 6 – Print the value of result variable to print the sum.
C Program
#include <stdio.h>
int sum(int k);
int main()
{
int num,result;
printf(“Enter a positive integer up to which you want sum “);
scanf(“%d”, &num);
result=sum(num);
printf(“Sum = %d”,result);
return 0;
}
int sum(int k)
{
if(k>0)
{
return (k+ sum(k- 1));
}
else
return 0;
}
Output
When we execute the above program and will enter the 10 as value of k then sum up from 1 to 10 it means 55 will be printed.
