How to echo text as asterisks

This is a discussion on How to echo text as asterisks within the C++ Programming forums, part of the General Programming Boards category; Just wondering how to echo user input (e.g. password) as asterisks? Any suggestions plz? Thom...

  1. #1
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    Question How to echo text as asterisks

    Just wondering how to echo user input (e.g. password) as asterisks?

    Any suggestions plz?

    Thom
    Before you criticise a man, walk a mile in his shoes. Then, when you criticise him, you're a mile away. And you have his shoes.

  2. #2
    Skunkmeister Stoned_Coder's Avatar
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    ive just answered this on the windows board. I hope you meant for windows....
    Dont cross post... pick the forum that best will solve the problem and stick with it.
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    Yeah sorry about that, I didn't actually mean to post it in the windows section.

    I meant in DOS, can it be done?

    I'm using Vis C++ 6, Win32 Console Application.

    Cheers.
    Before you criticise a man, walk a mile in his shoes. Then, when you criticise him, you're a mile away. And you have his shoes.

  4. #4
    zen
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    You can use getch() (in conio.h) to read characters without echo-ing them on the screen and then use cout<< or printf() to output an asterisk for every character read.

  5. #5
    Toaster Zach L.'s Avatar
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    As an example:

    Code:
    #include <iostream>
    #include <conio.h>
    
    const char ENTER = 13;
    
    int main()
    {
        char* str;
        char key;
        int i = 0;
        while(1)
        {
            key = getch();
            if(key == ENTER)
                break;
    
            str[i] = key;
            std::cout << '*';
            i++;
        }
        return 0;
    }

  6. #6
    and the hat of wrongness Salem's Avatar
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    > char* str;
    Uninitialised pointer alert!!!!!
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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  7. #7
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    Hehe I thought that, and I'm a newbeh!

    I'll give it a try though, thanks. Isn't there a simpler way?
    Before you criticise a man, walk a mile in his shoes. Then, when you criticise him, you're a mile away. And you have his shoes.

  8. #8
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    Write some code to start if off. It might be worthwhile to scan their input twice using different methods and compare the results to each other. Than if they match, compare it to a password key.
    I compile code with:
    Visual Studio.NET beta2

  9. #9
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    Erm... sorry I don't follow.

    Also, what is that .NET thing all about?

  10. #10
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    Code:
    #include<stdio.h>
    #include<conio.h>
    int main()
    {
    	char buffer[12];
    	int i, ch;
    
    	printf("Enter a password (10 alphanumeric sequenc max):\n" );
    	printf("Password: ");
    	
    	/* Read password but no larger than 10 characters */
    	for( i = 0; i < 10 ; i++ )
    	{
    		//get character
    		ch = _getch();
    		//if user enters newline than quit
    		if(ch == '\r') break;
    		//if user enters backspace
    		if(ch == '\b')
    		{
    			//if there are no preceeding letters
    			if(i == 0) 
    			{
    				--i;
    				continue;
    			}else //if there are preceeding letters
    			{
    				printf("\b%c\b",' ');
    				i-=2;
    			}
    		}else //no backspace was entered
    		{
    			putc('*',stdout);
    			buffer[i] = (char)ch;
    	
    		}
    	}
    	/* Terminate string with null character: */
    	buffer[i] = '\0';
    	printf( "\n%s", buffer);
    
    	return 0;
    }
    A little bit tricky. Works on Microsoft but not on *NIX
    If you wanted is cross platform than this should do it, chang this line:
    Code:
    if(ch == '\r') break;
    To this:
    Code:
    if(ch == '\r' || ch == '\n') break;
    Last edited by Witch_King; 09-02-2001 at 11:46 AM.
    I compile code with:
    Visual Studio.NET beta2

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