Tic Tac Toe overwritten array user inputs - c++

Question

The issue I am having is this:
I input a choice in square 1 "X" then it is O's turn so just to test things I input square 1 again. The error message pops up about it being an invalid square please enter another square. So I input a valid square and then the board gets drawn by the function and that's when I find out that the "X" in square one has been overwritten. This happens regardless of which character, X or O, is selected at the time. I'm kind of at my wits end and just looking for a little help with that part of the program. I figure once I hammer this part out the random number generator for the computers turn will be simple to implement, as well as checking for a win condition.
#include <iostream>
#include <cmath>
#include <string>
#include <cstdlib>
#include <ctime>
const int yCoordMax = 6;
const int xCoordMax = 2;
int xCoord;
int yCoord;
int square = 0;
const std::string PLAYER1 = "X";
const std::string COMPUTER = "O";
int turnCount = 0;
const int MAXTURN = 9;
int whoIsPlayer = 0; //denotes human with 0 and computer with 1 alternating between
std::string playerChar = " "; //the current turn's player's symbol
const std::string WIN = "You won!\n";
const std::string LOSE = "You lost.\n";
const std::string DRAW = "It's a draw.\n";
const std::string PLAY = "You will be the X's against the computer O's\n\n";
const std::string INSTRUCTIONS = "Enter the number of the square you wish to mark\nwith 1 being top left and 9 being bottom right.\n\n";
const std::string INVALIDSQUARE = "Please enter a correct square number between 1 and 9.\n";
const std::string SQUAREISFULL = "That square is already marked. Choose another.\n";
bool squareIsFilled[9] {0}; // any NON-Zero is true; ZERO is false
//array is zero thru eight
void drawBoard(void);
void convertSquareToCoordinates(std::string);
void validMove (int, std::string);
void drawMove(int, std::string, int, int);
void computerTurn(std::string);
std::string board[7][3] =
{ //0 //1 //2
{"+----", "+----+", "----+\n"}, // 0
{"| ", "| |", " |\n"}, // 1 input here only [1][0], [1][1], [1][2]
{"+----", "+----+", "----+\n"}, // 2
{"| ", "| |", " |\n"}, // 3 input here only [3][0], [3][1], [3][2]
{"+----", "+----+", "----+\n"}, // 4
{"| ", "| |", " |\n"}, // 5 input here only [5][0], [5][1], [5][2]
{"+----", "+----+", "----+\n"} // 6
};
int main()
{
std::srand(time(0));
std::cout << PLAY;
std::cout << INSTRUCTIONS;
drawBoard();
while (turnCount < MAXTURN)
{
if(whoIsPlayer == 0)
{
playerChar = PLAYER1;
convertSquareToCoordinates(playerChar);
whoIsPlayer = 1;
}
else
{
playerChar = COMPUTER;
convertSquareToCoordinates(playerChar);
whoIsPlayer = 0;
}
++turnCount;
}
return 0;
}
void drawBoard()
{
for (int y = 0; y <= yCoordMax; ++y)
{
for (int x = 0; x <= xCoordMax; ++x)
{
std::cout << board[y][x];
}
}
}
void convertSquareToCoordinates(std::string playerChar)
{
int square;
int yCoord;
int xCoord;
std::cout << std::endl;
std::cin >> square;
while(square < 1 || square > 9)
{
std::cout << INVALIDSQUARE;
std::cin >> square;
}
if (square == 1)
{yCoord = 1;
xCoord = 0;} //bool needs to flag invalid if square is filled
if (square == 2) //if square is empty then flag bool as filled
{yCoord = 1; //so validMove will skip execution
xCoord = 1;}
if (square == 3)
{yCoord = 1;
xCoord = 2;}
if (square == 4)
{yCoord = 3;
xCoord = 0;}
if (square == 5)
{yCoord = 3;
xCoord = 1;}
if (square == 6)
{yCoord = 3;
xCoord = 2;}
if (square == 7)
{yCoord = 5;
xCoord = 0;}
if (square == 8)
{yCoord = 5;
xCoord = 1;}
if (square == 9)
{yCoord = 5;
xCoord = 2;}
validMove(square, playerChar);
drawMove(square, playerChar, yCoord, xCoord);
}
void validMove(int square, std::string playerChar)
{
if(square == 1)
{
if(squareIsFilled[square - 1] == true){
if(whoIsPlayer == 0){
std::cout << SQUAREISFULL;}
convertSquareToCoordinates(playerChar);}
else
{squareIsFilled[square - 1] = true;}
}
if(square == 2)
{
if(squareIsFilled[square - 1] == true)
{if(whoIsPlayer == 0){
std::cout << SQUAREISFULL;}
convertSquareToCoordinates(playerChar);}
else
{squareIsFilled[square - 1] = true;}
}
if(square == 3)
{
if(squareIsFilled[square - 1] == true)
{if(whoIsPlayer == 0){
std::cout << SQUAREISFULL;}
convertSquareToCoordinates(playerChar);}
else
{squareIsFilled[square - 1] = true;}
}
// checks middle column for mark
if(square == 4)
{
if(squareIsFilled[square - 1] == true)
{if(whoIsPlayer == 0){
std::cout << SQUAREISFULL;}
convertSquareToCoordinates(playerChar);}
else
{squareIsFilled[square - 1] = true;}
}
if(square == 5)
{
if(squareIsFilled[square - 1] == true)
{if(whoIsPlayer == 0){
std::cout << SQUAREISFULL;}
convertSquareToCoordinates(playerChar);}
else
{squareIsFilled[square - 1] = true;}
}
if(square == 6)
{
if(squareIsFilled[square - 1] == true)
{if(whoIsPlayer == 0){
std::cout << SQUAREISFULL;}
convertSquareToCoordinates(playerChar);}
else
{squareIsFilled[square - 1] = true;}
}
// checks right column for mark
if(square == 7)
{
if(squareIsFilled[square - 1] == true)
{if(whoIsPlayer == 0){
std::cout << SQUAREISFULL;}
convertSquareToCoordinates(playerChar);}
else
{squareIsFilled[square - 1] = true;}
}
if(square == 8)
{
if(squareIsFilled[square - 1] == true)
{if(whoIsPlayer == 0){
std::cout << SQUAREISFULL;}
convertSquareToCoordinates(playerChar);}
else
{squareIsFilled[square - 1] = true;}
}
if(square == 9)
{
if(squareIsFilled[square - 1] == true)
{if(whoIsPlayer == 0){
std::cout << SQUAREISFULL;}
convertSquareToCoordinates(playerChar);}
else
{squareIsFilled[square - 1] = true;}
}
}
void drawMove(int square, std::string playerChar, int yCoord, int xCoord)
{
if(square == 1) //Draws left column move
board[yCoord][xCoord] = "| " + playerChar + " ";
else if(square == 2)
board[yCoord][xCoord] = "| " + playerChar + " |";
else if(square == 3)
board[yCoord][xCoord] = " " + playerChar + " |\n";
if(square == 4) //Draws middle column move
board[yCoord][xCoord] = "| " + playerChar + " ";
else if(square == 5)
board[yCoord][xCoord] = "| " + playerChar + " |";
else if(square == 6)
board[yCoord][xCoord] = " " + playerChar + " |\n";
if(square == 7) //Draws right column move
board[yCoord][xCoord] = "| " + playerChar + " ";
else if(square == 8)
board[yCoord][xCoord] = "| " + playerChar + " |";
else if(square == 9)
board[yCoord][xCoord] = " " + playerChar + " |\n";
drawBoard();
}

Answer 1

Look at convertSquareToCoordinates:
...
validMove(square, playerChar);
drawMove(square, playerChar, yCoord, xCoord);
If square refers to a square that is already filled, this function still calls drawMove on the corresponding (yCoord, xCoord).
More fundamentally, convertSquareToCoordinates and validMove call each other in a weird way. And your function names do not clearly describe what the functions are supposed to do.