Tic-tac-toe using classes, compute victory condition-CodePudding

I was trying to make a program for Tic-tac-toe between 2 players, using a class. But my is_victory function is always returning false. Why so?

//header file : tic_tac_toe.h
class Game
{
    public :
    Game();
    void insert(int , char);
    void print() const;
    bool is_empty(int) const;
    bool is_victory() const;
   
   
    private :
    char *pntr;
};

codefile:

// codefile for the class tic_tac_toe.cpp
#include"tic_tac_toe.h"
#include<iostream>

using namespace std;

Game::Game()
{
    pntr = new char[9] ;

    for(int i=0; i<9; i  )
    {
        pntr[i] = 48 i;
    }
}

void Game::insert(int location, char val)
{
    pntr[location] = val;
}

void Game::print() const
{
    for(int i=1; i<=9; i  )
    {
        cout<<pntr[i-1]<<"|";
        if(i%3 == 0) cout<<endl;
    }
}

bool Game::is_empty(int location) const
{
    if(pntr[location] == location 48 ) return true;
    else return false;
    
}

bool Game::is_victory() const
{
 if(pntr[0] == pntr[1] == pntr[2]) return true;
 if(pntr[3] == pntr[4] == pntr[5]) return true;
 if(pntr[6] == pntr[7] == pntr[8]) return true;
 if(pntr[0] == pntr[3] == pntr[6]) return true;
 if(pntr[1] == pntr[4] == pntr[7]) return true;
 if(pntr[2] == pntr[5] == pntr[8]) return true;
 if(pntr[0] == pntr[4] == pntr[8]) return true;
 if(pntr[2] == pntr[4] == pntr[6]) return true;

 return false;
}

Main program :

//tic_tac_toe_try1.cpp
#include"tic_tac_toe.h"
#include<iostream>

using namespace std;


int main()
{
    char player1;
    char player2;

    Game gameobj;

    cout<<"choose between X or O"<<endl;
    cin>> player1;

    if(player1 == 'X') player2='O';
    else player2 = 'X';
    
    for(int i=0; i<4; i  )
    {
        int location;

        gameobj.print();
        cout<<"enter location to enter "<< player1<<"between 0-8 as shown above : ";
        cin>> location;

        while(! (location>=0 && location<9) )
        {
            cout<<"invalid location ,  please renter location between 0-8: ";
            cin>>location;
        }

        while(!gameobj.is_empty(location) )
        {
           cout<<"invalid location , already filled please renter : ";
           cin>>location;
        }
        gameobj.insert(location, player1);
        gameobj.print();

        if(gameobj.is_victory()) 
        {
            cout<<"congrats player1 victorious";
            return 0;
        }

        

        cout<<"enter location to enter "<< player2<<"between 0-8 as shown above : ";
        cin>> location;

        while(! (location>=0 && location<9) )
        {
            cout<<"invalid location ,  please renter location between 0-8: ";
            cin>>location;
        }

        while(!gameobj.is_empty(location) )
        {
           cout<<"invalid location , already filled please renter : ";
           cin>>location;
        }
        gameobj.insert(location, player2);
        
           
        if(gameobj.is_victory()) 
        {
            cout<<"congrats player2 victorious";
            return 0;
        }
        
      
    }
    return 0;
}

Sample trial in terminal of vsc :

PS D:\c  > g   tic_tac_toe.cpp tic_tac_toe_try1.cpp
PS D:\c  > ./a.exe
choose between X or O
X
0|1|2|
3|4|5|
6|7|8|
enter location to enter Xbetween 0-8 as shown above : 0
X|1|2|
3|4|5|
6|7|8|
enter location to enter Obetween 0-8 as shown above : 3
X|1|2|
O|4|5|
6|7|8|
enter location to enter Xbetween 0-8 as shown above : 2
X|1|X|
O|4|5|
6|7|8|
enter location to enter Obetween 0-8 as shown above : 4
X|1|X|
O|O|5|
6|7|8|
enter location to enter Xbetween 0-8 as shown above : 1
X|X|X|
O|O|5|
6|7|8|
enter location to enter Obetween 0-8 as shown above :

As above even after getting 3 X's in 0,1,2 pntr's is_victory still doesn't give true.

I also tried checking the values of pntr[0], pntr[1], pntr[2] by manually printing them and the value of expression (pntr[0] == pntr[1] == pntr[2]) while the earlier all print X, but the comparison results in 0.

CodePudding user response：

if(pntr[0] == pntr[1] == pntr[2]) return true;

The condition A == B == C will be evaluated as (A == B) == C. The expression (A == B) will result in false (0) or true (1), and from the initialization of pntr we can see that C will never be equal to 0 nor 1. Therefore, the expression as a whole always evaluates to false.

What you probably meant to do is, e.g., this:

if(pntr[0] == pntr[1] && pntr[1] == pntr[2]) return true;