// An example of a C program with a function with
// one input and a return value

#include <stdio.h>

int sum_to(int n);

int main(void) {
    int max = 10;
    int result = sum_to(max);
    printf("Sum 1.. ");
    printf("%d", max);
    printf(" = ");
    printf("%d", result);
    putchar('\n');
    return 0;
}

// An iterative solution
int sum_to(int n) {
    int sum = 0;
    int i = 1;
sum_to_loop:
    if (i > n) goto sum_to_loop_end;    //while (i <= n) {
        sum = sum + i;
        i = i + 1;
    goto sum_to_loop;  
sum_to_loop_end:
    return sum;
}