Tic Tac Toe - passing variables -

[football52]

My error is happening on line 78 under the [m], it says identifier is undefined. I'm watching tutorial videos to get me through it and I have it set up the same way as them, but I'm running into an error that they seem to not run into

#include <iostream>
#include <string>
using namespace std;

char board[9];
int showBoard();
bool moveIsValid(int m);

int main()
{
	//declare local variables
	string playerOne;
	string playerTwo;
	int whoseTurn = 1;
	int move;

	//assign values to playing board
	board[0] = '1';
	board[1] = '2';
	board[2] = '3';
	board[3] = '4';
	board[4] = '5';
	board[5] = '6';
	board[6] = '7';
	board[7] = '8';
	board[8] = '9';

	//get players names
	cout << "What is the name of player 1?" << endl;
	getline(cin, playerOne);
	cout << "What is the name of player 2?" << endl;
	getline(cin, playerTwo);

	//do this until the player enters a valid move

	do
	{
		//show board
		showBoard();

		//Tell what player to move
		if (whoseTurn == 1)
		{
			cout << playerOne << ": It's your turn." << endl;

		}
		else
		{
			cout << playerTwo << ": It's your turn." << endl;
		}
		//get the move
		cout << "Enter the number of the spot where you would like to move." << endl;
		cin >> move;
	} while (moveIsValid(move) != true);

	//change whose turn it is
	switch (whoseTurn)
	{
	case(1) :
	{
				whoseTurn = 2;
				board[move] = 'X';
				break;
	}
	case(2) :
	{
				whoseTurn = 1;
				board[move] = 'O';
	}
	}
	//show board updated
	showBoard();
}
int showBoard()
{
	bool moveIsValid(int m);
	{
		if (board[m] != 'X' && board[m] != 'O')
		{
			return true;
		}
		else
		{
			return false;
		}
	}
	{
		cout << endl;
		cout << board[0] << " | " << board[1] << " | " << board[2] << endl;
		cout << "--+---+--" << endl;
		cout << board[3] << " | " << board[4] << " | " << board[5] << endl;
		cout << "--+---+--" << endl;
		cout << board[6] << " | " << board[7] << " | " << board[8] << endl;
		cout << endl;
	}
}

[18hRX9L8]

It's because you have a function in a function. Put the moveIsValid function and code outside of the showBoard function. Then delete the extra pair of curly-braces.

[football52]

When I do that I get a error on line 2 saying 'expected a declaration'

bool moveIsValid(int m);
{
	if (board[m] != 'X' && board[m] != 'O')
	{
		return true;
	}
	else
	{
		return false;
	}
}
int showBoard()
{
	cout << endl;
	cout << board[0] << " | " << board[1] << " | " << board[2] << endl;
	cout << "--+---+--" << endl;
	cout << board[3] << " | " << board[4] << " | " << board[5] << endl;
	cout << "--+---+--" << endl;
	cout << board[6] << " | " << board[7] << " | " << board[8] << endl;
	cout << endl;
}

[long double main]

Delete the semicolon after bool moveIsValid(int m).