Noughts and Crosses/Tic Tac Toe Player go again - c++

Question

Hi im new to c++ programming and am having trouble with my game. When a player chooses an already taken space or invalid move it skips their go. I would like for the player to be able to go again.
If there is any other problems you can see or any tips you can give me to tidy it up that would be great, or just any feedback.
Thank You
#include <iostream>
#include <conio.h>
#include <stdio.h>
#include <stdlib.h>
using namespace std;
char matrix[3][3] = { '1', '2', '3', '4', '5', '6', '7', '8', '9' };
int rear;
char player = 'X';
void mainMenu();
void play();
//strings for the player names to be chosen//
string charName = "Player1";
string charName2 = "Player 2";
//Noughts and Crosses//
int main()
{
system("Color 2E"); //Background and text colour//
mainMenu();
return 0;
}
void mainMenu()
{
system("CLS");
char userChoice = 'o';
do
{
//Main Menu//
cout << "\n Welcome to Noughts and Crosses" << endl
<< "\n\n 1. Play Game " << endl
<< " 2. How to Play" << endl
<< " 3. Who to refer to if the program malfunctions" << endl
<< " 4. Credits" << endl
<< " 5. Exit" << endl;
cout << "\n Please make a choice: ";
cin >> userChoice;
system("CLS");
if (userChoice == '1')
play();
else if (userChoice == '2')
cout <<
"\n\n\n Instructions:\n\n Enter the player names then press enter to proceed
with the game.\n To select the square you would like to place your marker enter the
square name followed by the ENTER key.\n Repeat this until a player has three of their
markers in a row. This can be in any direction.\n\n BE CAREFUL NOT TO CHOOSE AN ALREADY
TAKEN SPACE. OTHERWISE YOU WILL MISS A GO!!!\n\n Enjoy.\n\n\n"
<< endl;
else if (userChoice == '3')
cout << "\n\n\n Made in Visual Studios using C++\n Version 2.0\n\n" <<
endl;
else if (userChoice == '4')
cout << "\n\n\n Created by Jamie Clifford.\n Made in Visual Studios using
C++\n Version 2.0\n\n\n " << endl;
else if (userChoice == '5')
{
cout << " Good bye" << endl;
}
else
cout << " Error - Please choose again" << endl;
} while (userChoice != '5');
}
void Draw()
{
system("CLS");
//Board//
cout << "\n\n Noughts and Crosses \n\n";
for (int i = 0; i < 3; i++)
{
cout << " ";
for (int j = 0; j < 3; j++)
{
cout << matrix[i][j] << " ";
}
cout << endl;
}
}
void Input()
{
int a;
++rear;
player;
do
{
//Beginning of game, where player input their chosen space//
{ if (player == 'X')
cout << "\n It's " << charName << "'s turn. Enter a number: ";
else if (player == 'O')
cout << "\n It's " << charName2 << "'s turn. Enter a number: ";
}
cin >> a;
if (a == 1 && matrix[0][0] == '1')
matrix[0][0] = player;
else if (a == 2 && matrix[0][1] == '2')
matrix[0][1] = player;
else if (a == 3 && matrix[0][2] == '3')
matrix[0][2] = player;
else if (a == 4 && matrix[1][0] == '4')
matrix[1][0] = player;
else if (a == 5 && matrix[1][1] == '5')
matrix[1][1] = player;
else if (a == 6 && matrix[1][2] == '6')
matrix[1][2] = player;
else if (a == 7 && matrix[2][0] == '7')
matrix[2][0] = player;
else if (a == 8 && matrix[2][1] == '8')
matrix[2][1] = player;
else if (a == 9 && matrix[2][2] == '9')
matrix[2][2] = player;
else {
cout << "\n Invalid number, please try again.\n\n ";
system("pause");
rear--;
cin.ignore();
cin.get();
}
} while (a == -1);
}
void togglePlayer()
{
if (player == 'X')
player = 'O';
else player = 'X';
}
char Win()
{
//first player//
if (matrix[0][0] == 'X' && matrix[0][1] == 'X' && matrix[0][2] == 'X')
return 'X';
if (matrix[1][0] == 'X' && matrix[1][1] == 'X' && matrix[1][2] == 'X')
return 'X';
if (matrix[2][0] == 'X' && matrix[2][1] == 'X' && matrix[2][2] == 'X')
return 'X';
if (matrix[0][0] == 'X' && matrix[1][0] == 'X' && matrix[2][0] == 'X')
return 'X';
if (matrix[0][1] == 'X' && matrix[1][1] == 'X' && matrix[2][1] == 'X')
return 'X';
if (matrix[0][2] == 'X' && matrix[1][2] == 'X' && matrix[2][2] == 'X')
return 'X';
if (matrix[0][0] == 'X' && matrix[1][1] == 'X' && matrix[2][2] == 'X')
return 'X';
if (matrix[2][0] == 'X' && matrix[1][1] == 'X' && matrix[0][2] == 'X')
return 'X';
//second player//
if (matrix[0][0] == 'O' && matrix[0][1] == 'O' && matrix[0][2] == 'O')
return 'O';
if (matrix[1][0] == 'O' && matrix[1][1] == 'O' && matrix[1][2] == 'O')
return 'O';
if (matrix[2][0] == 'O' && matrix[2][1] == 'O' && matrix[2][2] == 'O')
return 'O';
if (matrix[0][0] == 'O' && matrix[1][0] == 'O' && matrix[2][0] == 'O')
return 'O';
if (matrix[0][1] == 'O' && matrix[1][1] == 'O' && matrix[2][1] == 'O')
return 'O';
if (matrix[0][2] == 'O' && matrix[1][2] == 'O' && matrix[2][2] == 'O')
return 'O';
if (matrix[0][0] == 'O' && matrix[1][1] == 'O' && matrix[2][2] == 'O')
return 'O';
if (matrix[2][0] == 'O' && matrix[1][1] == 'O' && matrix[0][2] == 'O')
return 'O';
return '/';
}
void play()
{//Players enter their names//
cout << "\n\n Player 1 enter your name: ";
cin >> charName;
cout << "\n\n Player 2 enter your name: ";
cin >> charName2;
char choice;
Draw();
Start:
while (1)
{
Input();
Draw();
if (Win() == 'X')
{
cout << "\n " << charName << " Wins The Game ";
break;
}
else if (Win() == 'O')
{
cout << "\n " << charName2 << " Wins The Game " << endl;
break;
}
else if (rear == 9)
{
cout << " Draw" << endl;
break;
}
togglePlayer();
}
//Choice to play the game again or return to the main menu//
cout << "\n\n ";
cout << " Do you want to go play again? ";
cout << "\n\n 1. Yes\n";
cout << " 2. No\n\n";
cout << " ";
cin >> choice;
if (choice == '1')
cout <<"\n Enjoy\n";
else if (choice == '2')
mainMenu();
while (choice != '1');
{
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
matrix[i][j] = i * 3 + (j + 1) + 48;
}
}
rear = 0;
player = 'X';
goto Start;
}
}

Answer 1

1. Indentation: You must indent what's inside the scopes ({}) so that it's possible to understand where loops/conditions start/end.
2. Global variables: You seem to be using a global variable rear. First of all global variables should be tagged like calling it g_rear so that whoever is reading the code knows it's a global variable. Second, it's not clear what this variable does from its name.
3. Possible infinite loop in line 242: while (choice != '1');
4. Use of goto: In general you should not use goto unless it's for error handling. The easiest way to debug/maintain code is if you know exactly the entry point into a piece of code and the exit point from that piece of code. A goto means you get to some point in the program in several different ways with the state of the program possibly being very different in each time.
5. Use loops instead of repeating yourself:
if (matrix[0][0] == 'X' && matrix[0][1] == 'X' && matrix[0][2] == 'X')
return 'X';
if (matrix[1][0] == 'X' && matrix[1][1] == 'X' && matrix[1][2] == 'X')
return 'X';
if (matrix[2][0] == 'X' && matrix[2][1] == 'X' && matrix[2][2] == 'X')
return 'X';
if (matrix[0][0] == 'X' && matrix[1][0] == 'X' && matrix[2][0] == 'X')
return 'X';
if (matrix[0][1] == 'X' && matrix[1][1] == 'X' && matrix[2][1] == 'X')
return 'X';
if (matrix[0][2] == 'X' && matrix[1][2] == 'X' && matrix[2][2] == 'X')
return 'X';
if (matrix[0][0] == 'X' && matrix[1][1] == 'X' && matrix[2][2] == 'X')
return 'X';
if (matrix[2][0] == 'X' && matrix[1][1] == 'X' && matrix[0][2] == 'X')
return 'X';
//second player//
if (matrix[0][0] == 'O' && matrix[0][1] == 'O' && matrix[0][2] == 'O')
return 'O';
if (matrix[1][0] == 'O' && matrix[1][1] == 'O' && matrix[1][2] == 'O')
return 'O';
if (matrix[2][0] == 'O' && matrix[2][1] == 'O' && matrix[2][2] == 'O')
return 'O';
if (matrix[0][0] == 'O' && matrix[1][0] == 'O' && matrix[2][0] == 'O')
return 'O';
if (matrix[0][1] == 'O' && matrix[1][1] == 'O' && matrix[2][1] == 'O')
return 'O';
if (matrix[0][2] == 'O' && matrix[1][2] == 'O' && matrix[2][2] == 'O')
return 'O';
if (matrix[0][0] == 'O' && matrix[1][1] == 'O' && matrix[2][2] == 'O')
return 'O';
if (matrix[2][0] == 'O' && matrix[1][1] == 'O' && matrix[0][2] == 'O')
return 'O';
Is a huge messy code, it's very difficult to see if there's a bug in it. Do the same with loops.
Same is true here:
if (a == 1 && matrix[0][0] == '1')
matrix[0][0] = player;
else if (a == 2 && matrix[0][1] == '2')
matrix[0][1] = player;
else if (a == 3 && matrix[0][2] == '3')
matrix[0][2] = player;
else if (a == 4 && matrix[1][0] == '4')
matrix[1][0] = player;
else if (a == 5 && matrix[1][1] == '5')
matrix[1][1] = player;
else if (a == 6 && matrix[1][2] == '6')
matrix[1][2] = player;
else if (a == 7 && matrix[2][0] == '7')
matrix[2][0] = player;
else if (a == 8 && matrix[2][1] == '8')
matrix[2][1] = player;
else if (a == 9 && matrix[2][2] == '9')
matrix[2][2] = player;
6. As for your actual question: Here:
else {
cout << "\n Invalid number, please try again.\n\n ";
system("pause");
rear--;
cin.ignore();
cin.get();
}
Change it to:
else {
cout << "\n Invalid number, please try again.\n\n ";
system("pause");
rear--;
cin.ignore();
cin.get();
a=-1;
}
To trigger the do ... while loop to make another cycle.

Answer 2

Just add in the else condition in Input()
a = -1;