Q:

Lower- to uppercase, printing words of one line under each other

I have to make a little c program that converts lowercase letters to uppercase. I have managed to do this, however, it's output is not yet completed.
The following is what I made so far:
#include <stdio.h>
#include <ctype.h>
#include <string.h>

int main(void){

char s[100];
int i;

gets(s);

for(i = 0; i < strlen(s); ++i)
{
    s[i] = toupper(s[i]);
}

printf (s);

}

If you'd insert 'this is a_test' it's output would be 'THIS IS A_TEST'. However, it should be the following:
'THIS
IS
A_TEST'
How do I do this?
Thanks in advance.

A:

for(i = 0; i < strlen(s); ++i) {
    if(s[i] = ' ')
        s[i] = '\n');
    else
        s[i] = toupper(s[i]);
}

