#include <stdio.h>
// prototype
int siguma_for(int n);
int siguma_while(int n);
int siguma_do(int n);
int siguma_rec(int n);

int siguma_for(int n)
{
    int r = 0;
    for (int i = 1; i <= n; ++i)
        r += i;
    return r;
}

int siguma_while(int n)
{
    int r = 0;
    while (n)
        r += n--;
    return r;
}

int siguma_do(int n)
{
    int r = 0;
    do r += n;
    while (--n);
    return r;
}

int siguma_rec(int n)
{
    return n ? n + siguma_rec(n - 1) : 0;
}

int main(void)
{
    int n = 10;
    printf("%d %d %d %d\n",
           siguma_for(n),
           siguma_while(n),
           siguma_do(n),
           siguma_rec(n) );
    return 0;
}