1+2+3+..........................+n

#include<stdio.h>

int main ()

// sum of 1+2+.......+n series in c programming language

{

int n,i;

int sum=0;

printf(''Enter the n th value: ")

scanf(''%d"&n);

sum=(n*(n+1))/2;

printf(''Sum of the series: ")

}