#include <stdio.h>
#include <string.h>

int main()
{
        char string[32];
        char *tmp;

        strcpy(string, "this is just a test");

        tmp = string;

        do {
                if ((tmp = strchr(tmp,' '))) {
                        *tmp = '!';
                        tmp++;
                }
        } while (tmp);

        printf("string: '%s'\n", string);

        return 1;
}