K&R exercise 1-23

/prog/ please help me.
I've been trying all evening to do this. I can't. I'm trying to do K&R exercise 1-23. Surely, I could look up the answer, but that isn't fun. Right now I'm trying to delete from '/*' and '*/' inclusive, ignoring whether it's between quotes or if it isn't. This is what I have so far:


#include <stdio.h>
main() {
    int c, i, t;
    while ((c = getchar()) != EOF) {
        if (c == '/' && (t = getchar()) == '*') {
            while (/*YOUR CONDITION HERE*/)
                ;
        } else if (c == '/'/* && t != '*'*/) {
            putchar(c);
            putchar(t);
        } else {
            putchar(c);
        }
    }
}
I have been thinking for a while what to put inside that while. I'm trying to put something that says "character is different from '*' and, if the previous condition is true, the next character is different from '/'". I tried with "c != '*' || (c = getchar()) != '/'" but that wouldn't work because whenever the first condition is true it loops infinitely, and the first condition will be true when it first checks it.

Use regular expressions, problem solved

One word: finite-state machine.

You can clean that up a lot by only getting one character per iteration and keeping the previous character somewhere, and having a state variable that determines whether you should be printing or not, and changing that state when you see /* or */, façon FSM. It'd make it easy to extend it to behave properly in the face of quoted strings, too.

>>1
You're reading K&R, but that's your main prototype? Start over, you have no business doing exercises on page 34 yet.

>>2
No.
>>4
I might try that. Thank you.
>>5
What do you mean? That's how the programs are in the examples so far.

K&R is outdated in this regard. Allow this to be your standard:

int main(void) {
    return 0;
}

#include <stdio.h>

int main(void)
{
    int in_string = 0, in_comment = 0;
    char c;

    while ((c = getchar()) != EOF) {
        if (in_comment) {
            if (c == '*')
                if ((c = getchar()) == '/')
                    in_comment = 0;
        } else if (!in_string && c == '/') {
            if ((c = getchar()) == '*')
                in_comment = 1;
            else {
                putchar('/');
                putchar(c);
            }
        } else {
            if (c == '"')
                in_string = !in_string;
            putchar(c);
        }
    }

    return 0;
}