#include <stdio.h>
#include <stdlib.h>

int debug = 1;


//This program demonstrates a way to use a debug variable to output debugging information
int main()
{
    int i, res=0, n;
    
    
    printf("enter a number: ");
    scanf("%d", &n);
    
    for(i=0; i<n; i++)
    {
         res = res + i;
         if(debug == 1)
         {
                printf("i = %d\tres=%d\n", i, res);  
         }
    }
    
    printf("res = %d\n", res);
    
    system("pause");
}