gistfile1.c

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

void wordrev(char* str)
{
    char *p, *r, *tp, *ip;
    p = str;
    tp = strchr(str, ' ');
    r = ip = !tp ? p + strlen(str)-1 : (tp==p ? tp : tp-1);
    while(1)
    {
        for(; p < r; p++, r--)
            *r ^= *p, *p ^= *r, *r ^= *p;
        if(*++ip == '\0')
            break;
        p = tp+1;
        tp = strchr(tp+1, ' ');
        r = !tp ? r + strlen(r)-1 : tp - 1;
        ip = r;
    }
}

int main()
{
    char str[] = " what     the fuck   gh a   i sldfkj  moonbase7";
    wordrev(str);
    puts(str);
    return 0;
}