Masking password input

You know when you enter a password and it's masked by '*'s? I've been trying to implement that, but with no luck. Here's an example:

Code:

int main() 
{
	char* in_pwd = (char*) calloc(20, sizeof (char));
 
	cout << "Password: ";
 
	// enter solution here :D
 
	// compare etc
 
	return 0;
}

Please don't moan about my use of char* and casts, that's not my problem (yet lol).

I figure I need to output a backspace then a '*' for each character input?

backspace in ASCII is 8:
char(8);

that doesn't work because you're putting the character into the console... and you could just use '\b' if you wanted a backspace

you have to catch the keystroke before it hits the cosole, and while there's no standard way to do it (AFAIK), you might want to look into the function getch();

FAQ > How do I... (Level 2) > How can I get input without having the user hit [Enter]?

Never mind I've solved it

Well, here's my "conio.h" version for all to enjoy anyways...

Code:

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

#include <conio.h>

bool get_password(string &password,
                  char echo_char = '*',    // echo character
                  bool esc_breaks = true,  // does hitting ESC return false?
                  size_t limit_length = 0) // is there a length limit?
{
    const int ESC = 27;
    const int BACKSPACE = 8;

    int c;
    vector<char> input;
    input.reserve(10);

    // clear password
    password.erase(password.begin(), password.end());

    for (;;)
    {
        c = getch();

        if (c == '\r')
        {
            input.push_back(0); // C-string terminator
            password = &input[0];
            break;
        }//if

        // only accept printable chars
        if (isprint(c))
        {
            if ((limit_length == 0) ||
                ((limit_length != 0) && (input.size() < limit_length)))
            {
                input.push_back(c);
                cout.put(echo_char);
            }//if
            else
            {
                cerr.put('\a');
            }//else
        }//if

        // support for backspace functionality
        if (c == BACKSPACE)
        {
            if (!input.empty())
            {
                cout.put(c);   // backspace
                cout.put(' '); // overwrite existing char
                cout.put(c);   // backspace back into position
                input.pop_back();
            }//if
            else
            {
                cerr.put('\a');
            }//else
        }//if

        if (esc_breaks && (c == ESC))
        {
            break;
        }//if
    }//for(;;)

    return !password.empty();
}//get_password

int main()
{
    string password;

    cout << "Enter Password: " << flush;

    if (get_password(password))
        cout << "\nYou entered: " << password << endl;
    else
        cout << "\nNo password entered." << endl;

    return 0;
}//main

gg

Do I have permission to use this in my program(s)?

you have permission to use my program. lol

Code:

#include <conio.h> 
#include <ctype.h> 
#include <iostream>

using namespace std;
int main()
{int l0l0lll0l0l0l;char l0l0lll0l[101];
 int l0l0lll0l0l = 0;
 cout<<"Enter your password>>";
 while ((l0l0lll0l0l0l = getch()) != EOF 
 && l0l0lll0l0l0l != '\n' && l0l0lll0l0l0l != '\r' 
 && l0l0lll0l0l < sizeof(l0l0lll0l) - 1)
{if (l0l0lll0l0l0l == '\b' && l0l0lll0l0l > 0) 
{printf("\b \b");fflush(stdout);
l0l0lll0l0l--;l0l0lll0l[l0l0lll0l0l] = '\0';}
else if (isalnum(l0l0lll0l0l0l)){cout<<"*";
l0l0lll0l[l0l0lll0l0l++] = (char)l0l0lll0l0l0l;}}
l0l0lll0l[l0l0lll0l0l] = '\0';cout<<""<<endl;
cout<<"You entered  <"<<l0l0lll0l<<">";
int l00l0ll0;cin>>l00l0ll0;return 0;}

This was just taken from FAQ anyway, Majorsmall's link

>> Do I have permission to use this in my program(s)?
Sure.

gg

Originally Posted by ahluka

Code:

int main() 
{
	char* in_pwd = (char*) calloc(20, sizeof (char));
 
	cout << "Password: ";
 
	return 0;
}

you need not to cast calloc, see the faq
http://faq.cprogramming.com/cgi-bin/...&id=1043284376
http://faq.cprogramming.com/cgi-bin/...&id=1043284351