[C++] Displaying Asterisk's for Password Characters ("*")?

[Calum Veteran]

I have recently been developing a program incorporating all the theory we learnt in the first year of university & it is going really well. However, I have a problem with my username & password code (something we never did in my first year).

I have a couple of minor problems but the only one I think I need help with is getting the password characters to all display as "*", in order to maintain privacy. I would like them to behave like actual characters so, for example, if I pressed backspace, I would want it to delete the last character & not display another asterisks.

I have not been able to find a solution to my problem anywhere. So please may somebody help?

I'd rather not change the whole code of my username & password function as I am happy with it at the moment, so would somebody please help me with how to implement this within my current code?

If I have to change the username & password function then I am willing to do so. Also, would anybody like me to display more of my code on this matter?

The following is the function which allows the user to enter the password (but not the whole of my username & password code as that is scattered around the program). I would assume it would have something to do with this line:

 cin >> password;

The whole function works perfectly as it should, I'd just like the password to be displayed with asterisk's :)

Here is my code anyway:

void authorisation(int& keyPressed, int& currentMonth, int& currentYear)
{
	 int getKeyPress();
	 void displayHeaderFooter( int& currentMonth, int& currentYear);
	 void loginSuccess(int& keyPressed, int& currentMonth, int& currentYear);

	 CLEAR_SCREEN();

	 displayHeaderFooter(currentMonth, currentYear);

	 ifstream Passfile("password.txt", ios::in);
	 Passfile >> inputPassword;
	 ifstream Userfile("username.txt", ios::in);
	 Userfile >> inputUsername;
   	 Gotoxy(24, 12);
	 SelectTextColour( clCyan);
	 cout << "Please enter your username.";
	 Gotoxy(42, 10);
	 cin >> username;
	 Gotoxy(24, 13);
	 SelectTextColour( clDarkCyan);
	 cout << "Please enter your password.";
	 Gotoxy(42, 11);
	 cin >> password;
	 Userfile.close();
	 Passfile.close();

	 userHeader = 1;

	 while (username == inputUsername && password == inputPassword)
	 {
		if (userHeader == 1)
		{
		Gotoxy(0, 0);
		SelectTextColour( clGrey);
		SelectBackColour( clDarkCyan);
		cout << "		" << username << "		  ";
		}

		 Gotoxy(23, 18);
		 SelectTextColour( clGreen);
		 SelectBackColour( clBlack);
		 cout << "You have logged in successfully.";
		 Gotoxy(15, 19);
		 cout << "Please press the 'M' key to display the Main Menu.";
		 loginSuccess(keyPressed, currentMonth, currentYear);
	 }


	 if (username != inputUsername || password != inputPassword)
	 {
		 Gotoxy(16, 18);
		 SelectTextColour( clRed);
		 cout << "\a";
		 cout << "The username or password you entered is invalid.";
		 Gotoxy(21, 19);
		 cout << "Please press the 'L' key to try again.";
		 keyPressed = getKeyPress();
		 if (keyPressed == 'L')
		 {
			 authorisation(keyPressed, currentMonth, currentYear);
		 }
		 else
		 {
			Gotoxy(16, 18);
			SelectTextColour( clRed);
			cout << "\a";
			cout << "	" << "The command you entered is invalid." << "	";
			Gotoxy(21, 19);
			cout << "	" << "Please press the 'L' key to login." << "	";
		 }
	 }

}

Thank you in advance. I would be very grateful for any help :)

Edited September 12, 2008 by cJr.

[dduardo]

cin is buffered so you'll have to use the raw file description functions to get the effect you want. Unfortunately, this type of stuff is non-standard, so you'll have to specify which OS your compiling/running this code on for us to better help you.

[Calum Veteran]

Thank you for your help & advice, although I don't really understand what you said (I'm still a beginner :()

I am using Windows Vista & at the moment I'm looking to make this application Windows only. It is a Win32 console application & I am using Visual Studio 2005 (rather than DevC++ or anything which sometimes have their own libraries).

Is there any more information you need?

[dduardo]

Here is how to do it on windows, with example code:

http://msdn.microsoft.com/en-us/library/078sfkak.aspx

----------------------

When I say cin is buffered, it means that when you press a key, the stuff your typing is stored in a buffer until you press the enter key.

An unbuffered input means that when you press a key, that value goes straight into the variable your using to store what's inputted.

A file descriptor is simply an integer that points to some input or output in the file descriptor table in the kernel, which has the actually address of the file (on disk or in memory) and other options

For example,

when you do something like:

FILE *j;

j = fopen('abc.txt', 'r');

You are essentially get back a integer, like 3. Then in the kernel there is a structure that has something like:

0 stdin 0x00203040

1 stdout 0x02340230

2 stderr 0x23423409234

3 "abc.txt" 0x20340304

This is a very simplistic view, but I think you'll get the idea.

[Andre S. Veteran]

I guess that will need its own routine, which you'll call from the authorisation routine. You'll have a loop that goes over each character using the aforementionned _getch_, and which will use a buffer (hm... maybe a vector<char>?) to, well, buffer all the characters and return a string when the enter key is pressed. Then if you want asteriks you just have to display a number of asteriks equal to the length of the buffer.

I'm not sure how you would implement the backspace functionality though.

[Joel]

The word you were looking for is 'asterisk'. Asterix is a comic book character.

[Calum Veteran]

Thank you both dduardo & Dr_Asik. There are a fair few things I don't understand completely in both your posts, however, I will have a look at them in detail when I get chance & research the parts I don't understand.

I will get back to you when I have had time to look at what you've said & try a few things (if I end up understanding how to implement the _getch(); code into my code lol :s)

  Joel said:

The word you were looking for is 'asterisk'. Asterix is a comic book character.

Thank you for informing me Joel. I'm surprised because my English is normally very good (especially as I didn't pick it up on Firefox's spell-checker either) :p

[AudioDope]

More importantly for those people who want to know how Asterix looks like:

[dduardo]

  Dr_Asik said:

I'm not sure how you would implement the backspace functionality though.

The easiest way to implement a password protection system is to simply don't print anything and ask for the password two times. This is how 99.99% of the command-line utilities do it.

But if you really want the asterisk blocked password you see in web-browsers than things get a little bit more complicated.

You'll want to use setConsoleCursorPosition and include 'windows.h'

http://msdn.microsoft.com/en-us/library/ms686025(VS.85).aspx

And do something like this:

COORD coord;

coord.X = x; coord.Y = y;

SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE), coord);

COORD is just a struct with x and y members

When ever you get a backspace code you'll move the cursor position back one and then write a space, then move the cursor back to the space to overwrite it when the user enters another character.

It seems like +cJr. is using some other library that uses gotoxy and has other console functions, but those aren't windows.h stuff, atleast from what i've found on msdn.

Edited September 12, 2008 by dduardo