#include<stdio.h>
#include<conio.h>
main()
{
    int n,i=0,sum=0;
    clrscr( );
    printf("Enter Limit : ");
    scanf("%d",&n);
    while(i<n)
    {
        i++;
        sum+=i;
    }
    printf("Sum of %d natural numbers = %d",n,sum);
    getch();
}

 OUTPUT:

Enter Limit : 10
Sum of 10 natural numbers = 55