Two-dimensional array of void function pointers c++

Question

I am trying to build an efficient Rock, Paper, Scissors simulator between 2 computer "players." A suggestion I saw here was to use a matrix to store the possible outcomes. I really liked this idea as it means I wouldn't have to have 9 different if() statements to account for all possible values. Whenever a match is completed I have functions to iterate the number of Wins, Losses, and Draws of each player. Thus, I thought it would be great if I could build a 2-dimensional array of function pointers so that [0][0] represents a throw of "Rock" by both parties and would result in a Draw, throwing the function addDraw() for each player. I found an example of a 1-dimensional array of function pointers which works here.

My code is throwing several errors when I try to compile. Let me know if anything else is needed.

Function to call the result:

void Player::result(vector<Player*> &vals, int x, int y)
{
    Player *p1 = vals[0];
    Player *p2 = vals[1];

    void(*results1[3][3]) =
    {
        { p1->addDraws, p1->addWins, p1->addLosses },
        { p1->addLosses, p1->addDraws, p1->addWins },
        { p1->addWins, p1->addLosses, p1->addDraws }
    };
}

Functions to add Wins, Losses, and Draws:

void Player::addWins()
{
    wins++;
}

void Player::addLosses()
{
    losses++;
}

void Player::addDraws()
{
    draws++;
}

All functions are initialized in Player.h and declared in Player.cpp (I think that's the right terms). The most common error I am receiving is "error C2440: 'initializing' : cannot convert from 'void (__thiscall Player::* )(void)' to 'void *'

Answer 1

You have an array of void pointers, not function pointers, and member functions are not function pointers.

You'll need something like

typedef void (Player::*Score)();  // typedefs and function types go together well
Score scores[3][3]) =
{
    { &Player::addDraws, &Player::addWins, &Player::addLosses },
    { &Player::addLosses, &Player::addDraws, &Player::addWins },
    { &Player::addWins, &Player::addLosses, &Player::addDraws }
};

// Calling
Player a;
(a.*scores[0][0])();

or, use free functions like this:

void addWins(Player* p)
{
    p->addWins();
}

// Similar for the others...

typedef void (*Score)();
Score scores[3][3] = {{ addWins, .... 

//
Player* player = ...
scores[0][0].addWins(player);

or, you can be modern and use std::function.