I need to choose random function in C++ project

I am making a C++ game-project and in the game I need to choose random bonuses (functions).

(below is the example of the code)

void triple_balls(){
    /* CODE */
}

void longer_paddle(){
    /* CODE */
}

void shorter_paddle(){
    /* CODE */
}

void bonus_activator(){
    //Here I must choose one of the 3 functions above
    //FIXME
}