calling a random function number

Question

I have a recurring problem that when I'm controlling leds, I make several different functions for different fx and just want to trigger them randomly but having a hard time to formulate it in an intelligent way and end up hardcoding every function call.

ex: I have let's say 10 functions called anim1();, anim2();, anim3(); etc and would like to called them randomly in that fashion :

randNumber = random(1,11);
anim[randNumber]();

I know that it's not that type of brackets I need to use but I can't find the proper syntax and I'm wondering if it's possible to do that.. I'm sure there must be a way ;)

thanks for your help

Answer 1

What you want is an array of function pointers.

void anim1() {
 // blah blah
}
void anim2() { 
 // blah blah
}
// ... etc ...
typedef void (*animptr)();
animptr anims[10] = {
 anim1,
 anim2,
 anim3,
 // ... etc ...
 anim10
};

Then you can use:

anims[animNumber]();

• Edgar Bonet: You mean typedef void (*animptr)();.
• Gerben: I didn't know this was possible. But I think I would feel dirty when using it. It just seems wrong to do this.
• Majenko: Why so? Function pointers are one of the most powerful facilities of C. Imagine trying to implement callbacks without being able to use function pointers - and an array of them is just an extension of that. A function is, after all, just a location in memory...
• robophil: thanks so much Majenko! exactly what i was looking for! :D

Answer 2

I end up using another way and just wanted to share it here for anybody that would want a bit less efficient but simpler way of doing that ;) it's cleaner with Majenko's solution for sure but this gets the job done and is pretty easy to understand and troubleshoot. cheers!

int randNumber;
void loop(){
randNumber = random(1,14);
if (button is pressed or something){
callAnim(randNumber);
}
}
void callAnim(int randNumber){
if (randNumber==1){
anim1();
}
if (randNumber==2){
anim2();
}
}
// ... etc ...
void anim1() {
// blah blah
}
void anim2() { 
// blah blah
}
// ... etc ...