CODEWITHSUNDEEP
c++pointers
Richard Escobia
Richard Escobia

Reputation: 1

How to access variables in a class using an array of objects?

I am new to pointers and I am having trouble in accessing the variables inside a class.

I want to make a sort of database of possible moves in a Chess game, and I think that using pointers is the way to go, since I wouldn't be wasting memory and prevent any unnecessary memory errors.

main.cpp

#include <iostream>
#include "moves.h"

using namespace std;

int main()
{
    moves* possibleMoves[100];
    &(possibleMoves[0]->piece) = 100;
    cout << *&possibleMoves[0]->piece << endl;
    return 0;
}

moves.h

#ifndef MOVES_H
#define MOVES_H


class moves
{
public:
    moves();
    int piece;
    int X;
    int Y;
    int addX;
    int addY;
    int score;
};

#endif // MOVES_H

Any help would be appreciated. Thank you very much in advance.

Currently it doesn't output anything and I don't know what to do.

Upvotes: 0

Views: 42

Answers (2)

mjc449
mjc449

Reputation: 114

You are creating an array of pointers with:

   moves* possibleMoves[100];

when what you want is an array of moves.

Then you are trying to assign piece in possibleMoves[0] a value of 100 with:

   &(possibleMoves[0]->piece) = 100;

but you are actually doing something quite different. As @Henri Menke said best to read up on &, *, . and ->.

To make your intended code work try:

int main()
{
    moves possibleMoves[100];
    possibleMoves[0].piece = 100;
    cout << possibleMoves[0].piece << endl;
    return 0;
}

Here you create an array of moves objects, then assign the value of piece in object 0 a value of 100. You retrieve the value and print it to cout.

Upvotes: 0

tdao
tdao

Reputation: 17678

I am having trouble in accessing the variables inside a class

It looks like you are making a mess of pointers and references.

There isn't a real need in your code to use array of pointers. Instead using normal array of objects would do.

moves possibleMoves[100];
possibleMoves[0].piece = 100;
cout << possibleMoves[0].piece << endl;

Btw, class moves incorrectly exposes all data members to public - they should be private. And moves constructor needs to be implemented or otherwise should be removed to use the default one.

Upvotes: 1

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