Need help with C Programming assignment

ok i'm pretty sure i got the code written for the substring and subsequence done, but am somewhat unsure of how to do the permutation fully. This is what i have so far

Code:

int permutation(char string1[], char string2[]);
{
int i, j;

for(i=0; string1[i]; i++;) {
         for(j=0; string2[j]; j++;) {
         if (string1[i] == string2[j])
            break;
         if (string[j] == '\0')
            return false;
            }
            }

the thing is i cant figure out where/how to phrase the return true statement. Also, since i havent tried it i may as well check, would the break statement exit out of both loops? or only the one?

and is string1[i] really a boolean expression to denote when its not null? or do i have to say like string[i] != '\0' ?

here are the other functions i had, if you care to double check. I havent debugged them yet.

substring

 Spoiler

Code:

int substring(char shortstr[], char longstr[])
{
    int i, j;
    
    for (i = 0; longstr[i]; i++){
        for (j=0; shortstr[j]; j++) {
            if longstr[i+j] != shortstr[j]
            break;
            if (shortstr[j] == '\0')
            return true;
            }
        }
    return false;
}

subsequence

 Spoiler

Code:

int subsequence(char shortstr[], char longstr[]);
{
    int i, j;
    j = 0;
    for (i = 0; longstr[i]; i++) {
        if (longstr[i] == shortstr[j])
                       j++;
                       }
        if (j == '\0')
           return true;
           else
           return false;
           }
}