/*
 * second.c
 */
#include <stdio.h>
int main()
{
    int n;

    printf("Enter a +ve integer: ");
    scanf("%d", &n);
    if(n <= 0) 
       printf("Incorrect data: %d\n", n);
    else printf("1+ ... +%d = %d\n", n, n*(n+1)/2);
    return 0;
} // second.c