skipping input?

Hello guys,

I'm writing a simple tic-tac-toe game just to get some practice with function (for those that read my previous post), and I have encounterd a problem which I've been trying to solve for sometime.

The problem is that if an invalid position has been entered and the lop goes back to the prompt again and a new CORRECT position has been entered it simply says it is wrong again.

Below I'm posting the two functions that handle that process.If anyone could help I would greaty appreciate it!

and by the way I don't know how to use arrays therefore it is all functions.

axon

Code:

//function switching the coordinates to the global vars
int switchCoordinatesToPosition(char letterPosition, int numberPosition, int&badMove)
{
	if( (letterPosition == 'A') && (numberPosition == 1) ) 
	{
		if(p1 != ' ') {badMove = -1;}
		else{ return 1; }
	}
	else if( (letterPosition == 'A') && (numberPosition == 2) )
	{
		if(p2 != ' ') {badMove = -1;}
		else{ return 2; }
	}
	else if( (letterPosition == 'A') && (numberPosition == 3) ) 
	{
		if(p3 != ' ') {badMove = -1;}
		else{ return 3; }
	}
	else if( (letterPosition == 'B') && (numberPosition == 1) ) 
	{
		if(p4 != ' ') {badMove = -1;}
		else{ return 4; }
	}
	else if( (letterPosition == 'B') && (numberPosition == 2) ) 
	{
		if(p5 != ' ') { badMove = -1;}
		else{ return 5; }
	}
	else if( (letterPosition == 'B') && (numberPosition == 3) ) 
	{
		if(p6 != ' ') { badMove = -1;}
		else{ return 6; }
	}
	else if( (letterPosition == 'C') && (numberPosition == 1) ) 
	{
		if(p7 != ' ') {badMove = -1;}
		else{ return 7; }
	}
	else if( (letterPosition == 'C') && (numberPosition == 2) ) 
	{
		if(p8 != ' ') { badMove = -1;}
		else{ return 8; }
	}
	else if( (letterPosition == 'C') && (numberPosition == 3) ) 
	{
		if(p9 != ' ') { badMove = -1;}
		else{ return 9; }
	}
	else { cout << "\nInvalid command...exiting!"; exit(-1);}	//default escape

}

//=================================================================================

	//function displaying the 'to move' prompt
void displayMovePrompt(char& playerValue, char& letterPosition, int& numberPosition, 
					   int& positionNumberOnBoard, int badMove)
{
	do
	{
		switch(playerValue){
			case 'X': cout << "\n\nPlayer X type in a move position: ";
				break;
			case 'O': cout << "\n\nPlayer O type in a move position: ";
				break;
		}
		cin >> letterPosition >> numberPosition;
	
		letterPosition = toupper(letterPosition);	//convert to CAPS

				//switch to position number
		positionNumberOnBoard = switchCoordinatesToPosition(letterPosition, numberPosition, badMove);

				//check for bad imput
		if(badMove == -1)
		{
			cout << "That is an invalid move!";
			badMove = -1;
		}
	}
	while(badMove == -1);
}

I guess I'll aswer myself then:

It works perfectly well when I initialized badMove to equal one inside the do statements.

Can anyone tell me exactlywhy this happens?

thanks

axon

attach the whole cpp file.

Originally posted by RoD
attach the whole cpp file.

I figured it out, but here is the attachments of the whole cpp file....warning...its still in development.

axon

Code:

/*
	Program:	Simple tic-tac-toe game
	Date:		02/21/03
*/


#include <iostream>
#include <cctype>
#include <cstdlib>
using namespace std;

	//declaring global variables for the positions on the board
char p1, p2, p3, p4, p5, p6, p7, p8, p9;

	//function displaying the game instructions
void displayInstructions()
{
	cout << "\tWelcome To TicTacToe!!\n\n"
		 << "Play against another player or the computer,\n"
		 << "     by choosing from the menu below.\n\n"
		 << "Enter positions as a letter and number.\n"
		 << "\t    ENJOY!!\n\n\n";
}

void displayMenu(int& menuOption)
{
	cout << "Choose from the following options:\n"
		 << "     1. Two Player Game\n"
		 << "     2. Single Player as 'X'\n"
		 << "     3. Single Player as 'O'\n"
		 << "Selection: ";
	cin >> menuOption;

	if(menuOption == 1)
		{cout << "\n\n   You chose a Single Player Game!\n\n";}
	else if(menuOption == 2)
		{cout << "\n\n   You chose to play against the computer as 'X'\n\n";}
	else if(menuOption == 3)
		{cout << "\n\n   You chose to play against the computer as 'O'\n\n";}
}

//================================================================================
	//function displaying the game board
void displayBoard()
{
	cout << "\n\n"
		 << "\t    1   2   3 \n"
		 << "\t A  "<<p1<<" | "<<p2<<" | "<<p3<<" \n"
		 << "\t   ----------- \n"
		 << "\t B  "<<p4<<" | "<<p5<<" | "<<p6<<"  \n"
		 << "\t   ----------- \n"
		 << "\t C  "<<p7<<" | "<<p8<<" | "<<p9<<"  \n\n";
	cout << endl;
}



//================================================================================
	//function switching the coordinates to the global vars
int switchCoordinatesToPosition(char letterPosition, int numberPosition, int&badMove)
{
	if( (letterPosition == 'A') && (numberPosition == 1) ) 
	{
		if(p1 != ' ') {badMove = -1;}
		else{ return 1; }
	}
	else if( (letterPosition == 'A') && (numberPosition == 2) )
	{
		if(p2 != ' ') {badMove = -1;}
		else{ return 2; }
	}
	else if( (letterPosition == 'A') && (numberPosition == 3) ) 
	{
		if(p3 != ' ') {badMove = -1;}
		else{ return 3; }
	}
	else if( (letterPosition == 'B') && (numberPosition == 1) ) 
	{
		if(p4 != ' ') {badMove = -1;}
		else{ return 4; }
	}
	else if( (letterPosition == 'B') && (numberPosition == 2) ) 
	{
		if(p5 != ' ') { badMove = -1;}
		else{ return 5; }
	}
	else if( (letterPosition == 'B') && (numberPosition == 3) ) 
	{
		if(p6 != ' ') { badMove = -1;}
		else{ return 6; }
	}
	else if( (letterPosition == 'C') && (numberPosition == 1) ) 
	{
		if(p7 != ' ') {badMove = -1;}
		else{ return 7; }
	}
	else if( (letterPosition == 'C') && (numberPosition == 2) ) 
	{
		if(p8 != ' ') { badMove = -1;}
		else{ return 8; }
	}
	else if( (letterPosition == 'C') && (numberPosition == 3) ) 
	{
		if(p9 != ' ') { badMove = -1;}
		else{ return 9; }
	}
	else { cout << "\nInvalid command...exiting!"; exit(-1);}	//default escape

}

//=================================================================================

	//function displaying the 'to move' prompt
void displayMovePrompt(char& playerValue, char& letterPosition, int& numberPosition, 
					   int& positionNumberOnBoard, int badMove)
{
	
	
	do
	{
		badMove=1;		
		switch(playerValue){
			case 'X': cout << "\n\nPlayer X type in a move position: ";
				break;
			case 'O': cout << "\n\nPlayer O type in a move position: ";
				break;
		}
		cin >> letterPosition >> numberPosition;
	
		letterPosition = toupper(letterPosition);	//convert to CAPS

				//switch to position number
		positionNumberOnBoard = switchCoordinatesToPosition(letterPosition, numberPosition, badMove);

				//check for bad imput
		if(badMove == -1)
		{
			cout << "That is an invalid move!";
			badMove = -1;
		}
	}
	while(badMove == -1);
}

//================================================================================
	//function making the move
void makeTheMove(int positionNumberOnBoard, char playerValue)
{
	switch(positionNumberOnBoard) {
		case 1: p1 = playerValue; break;
		case 2: p2 = playerValue; break;
		case 3: p3 = playerValue; break;
		case 4: p4 = playerValue; break;
		case 5: p5 = playerValue; break;
		case 6: p6 = playerValue; break;
		case 7: p7 = playerValue; break;
		case 8: p8 = playerValue; break;
		case 9: p9 = playerValue; break;
		default: cout << "Error !MaThMo!\n"; exit(-1); break;
	}

}

//=================================================================================
	

int main()
{
	p1=p2=p3=p4=p5=p6=p7=p8=p9=' ';		//setting the globals to " "

	bool notDone = true;

	char playerValue = 'X';		//setting the player value to X, as X starts
								//the game

	char letterPosition;		//value of the letter coordinate
	int numberPosition;			//value of the number coordinate
	int positionNumberOnBoard;
	int menuOption;				//value for the beginning menu
	int badMove;
	

	displayInstructions();		//displaying instructions
	displayMenu(menuOption);	//displaying the menu
	displayBoard();

	while(notDone)
	{
		if(menuOption == 1)
		{
			displayMovePrompt(playerValue, letterPosition, numberPosition,
							  positionNumberOnBoard, badMove); //displaying which player's move
		
			makeTheMove(positionNumberOnBoard, playerValue);

			displayBoard();
			
			//switchPlayers();
			
			//checkForMill();

			//areWeDone();
		}

	}

	return 0;
}