Thread: Passing a function as an argument

Sorry if this has been asked before but I couldn't find it anywhere. My question is how do you pass a function as an argument into another function. I don't mean pass the return value, I mean passing the function itself so the recieving funtion can use it as much as neccessary in order to get the values it needs.

Use a function pointer:

Code:

#include <stdio.h>

int square(int x) {
   return x * x;
}

int cube(int x) {
   return x * x * x;
}

void eval(int x, int (*func)(int)) {
   printf("%d\n", (*func)(x));
}

int main() {
   eval(3, &square);
   eval(3, &cube);
   return 0;
}

I put this function prototype, but it's generating quite a few compile errors. Mind telling me where I went wrong?

void DrawCollumn(char * (*RowText)(UINT)(DASMVIEWERINFO *), (DASMVIEWERINFO *) dvp);

Code:

char * (*RowText)(int, DASMVIEWERINFO *)

Its just like a normal function prototype except with a pointer star and parenthesis around the name.

Originally Posted by quzah

Here's a novel idea... How about posting your errors so we don't have to play guessing games?

Well, I figured the anwser would be obious enough to someone who'd done this kind of thing before I wouldn't have to.

Originally Posted by quzah

Hey, here's an even better idea, how about posting the function prototype of the function you expect to pass.

Beacuse I didn't write one yet .

Ah, good point. And yes that's what I meant to do. I edited my third post when I figured it out, but by that time two other people had already posted...