TTT(TicTacToe) C++

Question

I want to write a TicTacToe program with 2 players (I am doing an exercise from the Jumping into C++). The syntax below does not have any errors, but let's say i input 1 or 2, the program just exits without any errors or any results. Here is the code that i came up with:

#include <iostream>
using namespace std;


int board_pos;



int main()
{
cout << "Enter => 1 for X; 2 for O:" << endl;

enum TTT_Board{topLeft, topMid, topRight, middleLeft, middleMid, middleRight, botLeft, botMid, botRight};
cout << "-------" << endl;

cout << "|" << topLeft << "|" << topMid << "|" << topRight << "|" << endl; /* Top cells of the board */

cout << "-------" << endl;

cout << "|" << middleLeft << "|" << middleMid << "|" << middleRight << "|" << endl;

cout << "-------" << endl;

cout << "|" << botLeft << "|" << botMid << "|" << botRight << "|" << endl;

cout << "-------" << endl;

if (board_pos == 0){
    switch (board_pos) {
        case topLeft:
            cout << " " << endl;
            break;
        case topMid:
            cout << " " << endl;
            break;
        case topRight:
            cout << " " << endl;
            break;
        case middleLeft:
            cout << " " << endl;
            break;
        case middleMid:
            cout << " " << endl;
            break;
        case middleRight:
            cout << " " << endl;
            break;
        case botLeft:
            cout << " " << endl;
            break;
        case botMid:
            cout << " " << endl;
            break;
        case botRight:
            cout << " " << endl;
            break;


        default:
            break;
    }

}
else if (board_pos == 1)
{
    switch (board_pos) {
        case topLeft:
            cout << "X" << endl;
            break;
        case topMid:
            cout << "X" << endl;
            break;
        case topRight:
            cout << "X" << endl;
            break;
        case middleLeft:
            cout << "X" << endl;
            break;
        case middleMid:
            cout << "X" << endl;
            break;
        case middleRight:
            cout << "X" << endl;
            break;
        case botLeft:
            cout << "X" << endl;
            break;
        case botMid:
            cout << "X" << endl;
            break;
        case botRight:
            cout << "X" << endl;
            break;


        default:
            break;
    }
}
else if (board_pos == 2)
{
    switch (board_pos) {
        case topLeft:
            cout << "O" << endl;
            break;
        case topMid:
            cout << "O" << endl;
            break;
        case topRight:
            cout << "O" << endl;
            break;
        case middleLeft:
            cout << "O" << endl;
            break;
        case middleMid:
            cout << "O" << endl;
            break;
        case middleRight:
            cout << "O" << endl;
            break;
        case botLeft:
            cout << "O" << endl;
            break;
        case botMid:
            cout << "O" << endl;
            break;
        case botRight:
            cout << "O" << endl;
            break;


        default:
            break;
    }
}
else {
    cout << "Please enter: 1 for X, 2 for O, and 0 if you want you skip the cell";

}
cin >> board_pos;


}

NOTE: The Program does compile!

Answer 1

You are recursively calling main().

The standard states :

3.6.1.3

"The function main shall not be used within a program."

5.2.2.9

"Recursive calls are permitted, except to the function named main"

And you are reading the user input after this recursive call to main(), which, if this call ever succeed, will let no chance to your user to enter anything.

A program that compiles is not necessarily in good program.