Thread: Help on restricting input to a numbers only (or text only)

My question is how can I restrict a users input to numbers only or letters only. I'd post my source code, but it's only half commented.

Well, it would be good if you posted the smallest and simplest program that demontrates just this part of the program, or at least what you have tried so far.

Still, on a hunch I can suggest that you look through and try this program:

Code:

#include <iostream>
#include <limits>

int main()
{
	int num;
	std::cout << "Enter an integer: ";
	while (!(std::cin >> num))
	{
		// reset the status of the stream
		std::cin.clear();
		// ignore remaining characters in the stream
		std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
		std::cout << "Enter an *integer*: ";
	}
	std::cout << "You entered: " << num << std::endl;
}

Could that be switched round so that it only continues when the user inputs nothing?

Thanks you guys. After a little bit of experimenting with it, I was able to get it to do what I wanted.

Now what do I need to switch if I want it to only read chars and not integers?

EDIT: Well, I thought it worked. It works in the sense that it solves my input only numbers problem. But now, it won't show my errors for when the user inputs more than they have or less than a dollar.

Here's the source for the bet() function:

Code:

void bet()	// bet() function
{
	do {	// start of Do While loop
		clrscrn();	// Clears the screen
		SetConsoleTextAttribute(hOut, FBI);	// Sets the text color to bright blue
		cout<<"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n";	// ASCII graphics
		cout<<"~~~~~~~~~ ";	// Ascii graphics
		SetConsoleTextAttribute(hOut, FWI);	// Sets the text color to bright white
		cout<<"How much would you like to bet? ";
		SetConsoleTextAttribute(hOut, FBI);	// Sets the text color to bright blue
		cout<<"~~~~~~~~\n";						//
		cout<<"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n";	//
		cout<<"~~~                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n";	// Rest of ASCII graphics
		cout<<"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~               ~~~\n";	//
		cout<<"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n";	//
		Position.X = 4;
		Position.Y = 3;
		SetConsoleCursorPosition(hOut, Position);
		SetConsoleTextAttribute(hOut, FGI);
		cout<<"Money: $"<< money;
		Position.X = 33;
		Position.Y = 4;
		SetConsoleCursorPosition(hOut, Position);
		cout<<"Bet: $";
		
		while (!(std::cin >> amountbet))
		{
			// reset the status of the stream
			std::cin.clear();
			// ignore remaining characters in the stream
			std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
			Position.X = 0;
			Position.Y = 6;
			SetConsoleTextAttribute(hOut, FRI);
			SetConsoleCursorPosition(hOut, Position);
			std::cout << "\aYou must enter a number.\n";
			Position.X = 39;
			Position.Y = 4;
			SetConsoleCursorPosition(hOut, Position);
			cout<<" ";
			SetConsoleCursorPosition(hOut, Position);
			SetConsoleTextAttribute(hOut, FGI);
		}

		Position.X = 0;
		Position.Y = 6;
		SetConsoleCursorPosition(hOut, Position);
		if ( amountbet > 0 && amountbet <= money )
		{
			betloop1 = 1;
		}
		else if ( amountbet <=0 )
		{
			betloop1 = 0;
			SetConsoleTextAttribute(hOut, FRI);
			cout<<"!!!!!!!!!! You must bet at least $0.01 !!!!!!!!!!!\n\n";
			cout<<"Press enter to try again.\n";
			cin.get();
		}
		else if ( amountbet > money )
		{
			betloop1 = 0;
			SetConsoleTextAttribute(hOut, FRI);
			cout<<"!!!!!!!!!! You don't have enough money !!!!!!!!!!!\n\n";
			cout<<"Press enter to try again.\n";
			cin.get();
		}
		else
		{
			error();
		}
	} while ( betloop1 !=1 );
	do {
		clrscrn();
		SetConsoleTextAttribute(hOut, FBI);
		cout<<"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n";
		cout<<"~~~~~~~~~~ "; 
		SetConsoleTextAttribute(hOut, FWI);
		cout<<"What number (2-12) to bet on";
		SetConsoleTextAttribute(hOut, FBI);
		cout<<" ~~~~~~~~~~\n";
		cout<<"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n";
		cout<<"~~~                      ~~~~~~~~~~~~~~~~~~~~~~~~~\n";
		cout<<"~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n";
		Position.X = 4;
		Position.Y = 3;
		SetConsoleCursorPosition(hOut, Position);
		SetConsoleTextAttribute(hOut, FCI);
		cout<<"Number to bet on: ";

		while (!(std::cin >> numberbet))
		{
			std::cin.clear();
			std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
			Position.X = 0;
			Position.Y = 5;
			SetConsoleCursorPosition(hOut, Position);
			SetConsoleTextAttribute(hOut, FRI);
			std::cout<<"\aYou must enter a number.\n";
			std::cout<<"Please try again.";
			Position.X = 22;
			Position.Y = 3;
			SetConsoleCursorPosition(hOut, Position);
			std::cout<<" ";
			SetConsoleCursorPosition(hOut, Position);
			SetConsoleTextAttribute(hOut, FCI);
		}

		Position.X = 0;
		Position.Y = 5;
		SetConsoleCursorPosition(hOut, Position);
		if ( numberbet >= 2 && numberbet <= 12 )
		{
			betloop2 = 1;
		}
		else if ( numberbet < 2 || numberbet > 12 )
		{
			betloop2 = 0;
			SetConsoleTextAttribute(hOut, FRI);
			cout<<"!!!!!!!!!!!! You can only choose 2-12 !!!!!!!!!!!!\n\n";
			cout<<"Press enter to try again.\n";
			cin.get();
		}
		else
		{
			error();
		}
	} while ( betloop2 != 1 );
}

The compiled program is attached for those who want to see what I'm talking about. Just change the .cpp extension to .zip and unzip it like normal. (compiled on WinXP using Borland compiler).