Write a c program to find out the sum of series 1 + 2 + …. + n.

C Code:

#include<stdio.h>

int main(){

    int n,i;

    int sum=0;

    printf("Enter the n i.e. max values of series: ");

    scanf("%d",&n);

    sum = (n * (n + 1)) / 2;

    printf("Sum of the series: ");

    for(i =1;i <= n;i++){

         if (i!=n)

             printf("%d + ",i);

         else

             printf("%d = %d ",i,sum);

         }

   

    return 0;

}

Sample output:

Enter the n i.e. max values of series: 5

Sum of the series: 1 + 2 + 3 + 4 + 5 = 15

Mathematical Formula:

Sum of the series 1 + 2 + 3 + … + n = n (n+1)/2