Randomly choosing a preset function in C Programming

Question

I have a list of different functions in my main():

puzzle1(ar); 
puzzle2(ar); 
puzzle3(ar); 
puzzle4(ar); 
puzzle5(ar);

I want to randomly pick only one of the functions to be called. What should I do to make this happen?

Thank you!

EDIT 1:My functions are all 2D-Arrays

EDIT 2: Got more help from comments.

EDIT 3:After more help, I've done the following:

srand(time(NULL));
int rand_output = rand()%5;
int (*fp[5])(char finalpuzzle[NROW][NCOL]);


int main();

char ar[NROW][NCOL];
int x,y,fp=0;

    fp[0]=puzzle1;
    fp[1]=puzzle2;
    fp[2]=puzzle3;
    fp[3]=puzzle4;
    fp[4]=puzzle5;
    (*fp[rand_output])(x,y);

What am I doing wrong? Errors I'm obtaining are :

expected declaration specifier or '.....' before 'time'

on the srand line

initializer element is not constant

on the int rand_output line

subscripted value is neither array nor pointer nor vector

on the (*fp[rand_output])(x,y) line

and a bunch of warning that says initialization from incompatible pointer type

Answer 1

Use rand() to select one index and call the function at that index from a list of function pointers.

srand(time(NULL));   // called once
int rand_output = rand()%5; 
int (*fp[5]) (int ar[]);

..
..
fp[0]=puzzle1;
fp[1]=puzzle2;
..

(*fp[rand_output])(arr);

Or simply in one line:-

 int (*fp[5])(int[])={puzzle1, puzzle2,. ...., puzzle5};

A small example code

#include<stdio.h>
#include<stdlib.h>
#include<time.h>

void op1(int ar[][2]){
    printf("%s","ok");
}
void op2(int ar[][2]){
    printf("%s","ok2");
}
int main(){
    int z[2][2]={{0,1},{2,4}};
    srand(time(NULL));   // called once
    int rand_output = rand()%2; 
    void (*fp[2]) (int ar[][2]);
    fp[0]=op1;
    fp[1]=op2;
    (*fp[rand_output])(z);
}