Reputation: 1035
Tic Tac Toe game won't work
So I learnt programming about a week ago. I decided to make a tic tac toe game as a hobby project, I got a rudimentary game input method up and running but one aspect doesn't work. I made a very simplified piece of code to verify if somebody has won once 5 moves have been played. Once somebody wins, it's supposed to display "Game Over!" but it doesn't for some reason. Can anyone help?_____________ Note: The method to verify if somebody has won yet isn't complete in the code. It is only for rows because when I tested it, it didn't work.
#include <iostream>
#include <cstdlib>
using namespace std;
int main()
{
char grid[3][3];
int p;
cout << "Enter column number. \n";
cin >> p;
int o;
cout << "Enter row number. \n";
cin >> o;
for (int y = 0; y < 3; y++)
{
for (int x = 0; x < 3; x++)
{
grid[x][y] = '-';
grid[o][p] = 'X';
cout << grid[x][y] << " ";
}
cout << endl;
}
int q;
cout << "Enter column number. \n";
cin >> q;
int r;
cout << "Enter row number. \n";
cin >> r;
for (int y = 0; y < 3; y++)
{
for (int x = 0; x < 3; x++)
{
grid[x][y] = '-';
grid[o][p] = 'X';
grid[r][q] = 'O';
cout << grid[x][y] << " ";
}
cout << endl;
}
int s;
cout << "Enter column number. \n";
cin >> s;
int t;
cout << "Enter row number. \n";
cin >> t;
for (int y = 0; y < 3; y++)
{
for (int x = 0; x < 3; x++)
{
grid[x][y] = '-';
grid[o][p] = 'X';
grid[r][q] = 'O';
grid[t][s] = 'X';
cout << grid[x][y] << " ";
}
cout << endl;
}
int v;
cout << "Enter column number. \n";
cin >> v;
int b;
cout << "Enter row number. \n";
cin >> b;
for (int y = 0; y < 3; y++)
{
for (int x = 0; x < 3; x++)
{
grid[x][y] = '-';
grid[o][p] = 'X';
grid[r][q] = 'O';
grid[t][s] = 'X';
grid[b][v] = 'O';
cout << grid[x][y] << " ";
}
cout << endl;
}
int f;
cout << "Enter column number. \n";
cin >> f;
int g;
cout << "Enter row number. \n";
cin >> g;
for (int y = 0; y < 3; y++)
{
for (int x = 0; x < 3; x++)
{
grid[x][y] = '-';
grid[o][p] = 'X';
grid[r][q] = 'O';
grid[t][s] = 'X';
grid[b][v] = 'O';
grid[g][f] = 'X';
cout << grid[x][y] << " ";
}
cout << endl;
}
if (grid[0][0] == grid[0][1] == grid[0][2] || grid[1][0] == grid[1][1] == grid[1][2] || grid[2][0] == grid[2][1] == grid[2][2])
{
cout << "Game Over! \n\n";
}
int i;
cout << "Enter column number. \n";
cin >> i;
int u;
cout << "Enter row number. \n";
cin >> u;
for (int y = 0; y < 3; y++)
{
for (int x = 0; x < 3; x++)
{
grid[x][y] = '-';
grid[o][p] = 'X';
grid[r][q] = 'O';
grid[t][s] = 'X';
grid[b][v] = 'O';
grid[g][f] = 'X';
grid[u][i] = 'O';
cout << grid[x][y] << " ";
}
cout << endl;
}
if (grid[0][0] == grid[0][1] == grid[0][2] || grid[1][0] == grid[1][1] == grid[1][2] || grid[2][0] == grid[2][1] == grid[2][2])
{
cout << "Game Over! \n\n";
}
int a1;
cout << "Enter column number. \n";
cin >> a1;
int e1;
cout << "Enter row number. \n";
cin >> e1;
for (int y = 0; y < 3; y++)
{
for (int x = 0; x < 3; x++)
{
grid[x][y] = '-';
grid[o][p] = 'X';
grid[r][q] = 'O';
grid[t][s] = 'X';
grid[b][v] = 'O';
grid[g][f] = 'X';
grid[u][i] = 'O';
grid[e1][a1] = 'X';
cout << grid[x][y] << " ";
}
cout << endl;
}
if (grid[0][0] == grid[0][1] == grid[0][2] || grid[1][0] == grid[1][1] == grid[1][2] || grid[2][0] == grid[2][1] == grid[2][2])
{
cout << "Game Over! \n\n";
}
int a8;
cout << "Enter column number. \n";
cin >> a8;
int b8;
cout << "Enter row number. \n";
cin >> b8;
for (int y = 0; y < 3; y++)
{
for (int x = 0; x < 3; x++)
{
grid[x][y] = '-';
grid[o][p] = 'X';
grid[r][q] = 'O';
grid[t][s] = 'X';
grid[b][v] = 'O';
grid[g][f] = 'X';
grid[u][i] = 'O';
grid[e1][a1] = 'X';
grid[b8][a8] = 'O';
cout << grid[x][y] << " ";
}
cout << endl;
}
if (grid[0][0] == grid[0][1] == grid[0][2] || grid[1][0] == grid[1][1] == grid[1][2] || grid[2][0] == grid[2][1] == grid[2][2])
{
cout << "Game Over! \n\n";
}
int a9;
cout << "Enter column number. \n";
cin >> a9;
int b9;
cout << "Enter row number. \n";
cin >> b9;
for (int y = 0; y < 3; y++)
{
for (int x = 0; x < 3; x++)
{
grid[x][y] = '-';
grid[o][p] = 'X';
grid[r][q] = 'O';
grid[t][s] = 'X';
grid[b][v] = 'O';
grid[g][f] = 'X';
grid[u][i] = 'O';
grid[e1][a1] = 'X';
grid[b8][a8] = 'O';
grid[b9][a9] = 'X';
cout << grid[x][y] << " ";
}
cout << endl;
}
if (grid[0][0] == grid[0][1] == grid[0][2] || grid[1][0] == grid[1][1] == grid[1][2] || grid[2][0] == grid[2][1] == grid[2][2])
{
cout << "Game Over! \n\n";
}
}
Upvotes: 0
Views: 301
Answers (3)
Reputation: 57678
Your program would be a lot smaller if you used one array and number the boxes 1 through 9:
+---+---+---+
| 1 | 2 | 3 |
+---+---+---+
| 4 | 5 | 6 |
+---+---+---+
| 7 | 8 | 9 |
+---+---+---+
The array would like this:
const unsigned int BOARD_CAPACITY = 9;
unsigned int board[BOARD_CAPACITY + 1];
The board array is declared with one extra slot so you can safely use indices 1 through 9.
A single row check:
bool row_wins = false;
if ((board[1] == board[2]) && (board[2] == board[3]))
{
row_wins = true;
}
Upvotes: 1
Reputation: 17926
In C++, the == sign doesn't work the way it does in algebra class. The expression a == b == c has a very different meaning in C++. In C++, it only works on pairs of items, and returns a true or false value. (See more below.)
To see if 3 things all equal each other, you need to say (a == b && b == c). Your grid check would need to look like this:
if ( (grid[0][0] == grid[0][1] && grid[0][1] == grid[0][2]) ||
(grid[1][0] == grid[1][1] && grid[1][1] == grid[1][2]) ||
(grid[2][0] == grid[2][1] && grid[2][1] == grid[2][2]) )
You'll also notice I put extra parentheses in there. They are not strictly necessary, but some compilers warn when you mix && and || in the same expression. The parentheses make it clear which items you intend to group together and will quell those warnings.
So what was the C++ compiler doing with your code? You had written grid[0][0] == grid[0][1] == grid[0][2]. The compiler interprets that as (grid[0][0] == grid[0][1]) == grid[0][2] according to its operator precedence rules.
The compiler will first compare grid[0][0] to grid[0][1]. This will produce a true or false boolean value (C++ bool) depending on whether they were equal. So far, so good.
After the comparison, it will compare that bool result against grid[0][2]. Since grid[0][2] is a char, it promotes the bool to a numeric value. true becomes 1 and false becomes 0. None of your grid values have the value 0 or 1—they are all either '-', 'X' or 'O'—so the second comparison always fails.
The same situation repeats for all three rows.
Upvotes: 5
Reputation: 12738
For my understanding you cannot write:
grid[0][0] == grid[0][1] == grid[0][2]
You should have:
grid[0][0] == grid[0][1] && grid[0][1]== grid[0][2]
In C++ these are binary operators, and thus == can only be applied to two variables, not chained to three. Now it compares first result (true/false) to the third number.
My sources:
Upvotes: 3
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