How do I display star(*) instead of plain text for password c++

Question

How can I do so that I can display star(*) instead of plain text for password in C++.

I am asking for password and it is plain pass on the screen.

How can I convert them in to star(*) so that user can not see the password while entering.

This is what I have currently

        char pass[10]={"test"};
        char pass1[10];
        textmode(C40);
        label:
        gotoxy(10,10);
        textcolor(3);
        cprintf("Enter password :: ");
        textcolor(15);
        gets(pass1);
        gotoxy(10,11);
        delay(3000);
        if(!(strcmp(pass,pass1)==0))
        {
          gotoxy(20,19);
          textcolor(5);
          cprintf("Invalid password");
          getch();
          clrscr();
          goto label;
        }

Thanks

possible duplicate of [C++ password masking](http://stackoverflow.com/questions/2522754/c-password-masking) — Björn Pollex, May 30 '11 at 11:07
Also, [this](http://stackoverflow.com/questions/1413445/). An please - don't use `goto`. — Björn Pollex, May 30 '11 at 11:09

score 7 · Accepted Answer · answered May 30 '11 at 11:11

You need to use an unbuffered input function, like getch () provided by curses library, or a console library of your OS. Calling this function will return the pressed key character, but will not echo. You can manually print * after you read each character with getch (). Also you need to write code if backspace is pressed, and appropriately correct the inserted password.

Here is a code which once i wrote with the curses. Compile with gcc file.c -o pass_prog -lcurses

#include <stdio.h>
#include <stdlib.h>
#include <curses.h>

#define ENOUGH_SIZE 256

#define ECHO_ON 1
#define ECHO_OFF 0

#define BACK_SPACE 127

char *my_getpass (int echo_state);

int main (void)
{
  char *pass;

  initscr ();

  printw ("Enter Password: ");
  pass = my_getpass (ECHO_ON);

  printw ("\nEntered Password: %s", pass);
  refresh ();
  getch ();
  endwin ();
  return 0;
}


char *my_getpass (int echo_state)
{
  char *pass, c;
  int i=0;

  pass = malloc (sizeof (char) * ENOUGH_SIZE);
  if (pass == NULL)
  {
    perror ("Exit");
    exit (1);
  }

  cbreak ();
  noecho ();

  while ((c=getch()) != '\n')
  {
    if (c == BACK_SPACE)
    {
      /* Do not let the buffer underflow */
      if (i > 0)
      { 
        i--;
        if (echo_state == ECHO_ON)
               printw ("\b \b");
      }
    }
    else if (c == '\t')
      ; /* Ignore tabs */
    else
    {
      pass[i] = c;
      i = (i >= ENOUGH_SIZE) ? ENOUGH_SIZE - 1 : i+1;
      if (echo_state == ECHO_ON)
        printw ("*");
    }
  }
  echo ();
  nocbreak ();
  /* Terminate the password string with NUL */
  pass[i] = '\0';
  endwin ();
  return pass;
}

it throws error when I include `curses.h` file `unable to open include file`. Can you please let me know why this is unable to include that file — Daric, May 30 '11 at 11:29
because probably you do not have the curses library installed in your system. What system are you working in ? which OS ? — phoxis, May 30 '11 at 12:15

score 5 · Answer 2 · answered May 30 '11 at 11:12

There's nothing in C++ per se to support this. The functions in your example code suggest that you are using curses, or something similar; if so, check the cbreak and nocbreak functions. Once you've called cbreak, it's up to you to echo the characters, and you can echo whatever you like (or nothing, if you prefer).

score 2 · Answer 3 · answered Dec 13 '14 at 07:22

2

#include<iostream.h>
#include<conio.h>
#include<stdio.h>
void main()
{
 clrscr();
 char a[10];
 for(int i=0;i<10;i++)
 {
  a[i]=getch();     //for taking a char. in array-'a' at i'th place 
  if(a[i]==13)      //cheking if user press's enter 
  break;            //breaking the loop if enter is pressed  
  printf("*");      //as there is no char. on screen we print '*'
 }
 a[i]='\0';         //inserting null char. at the end
 cout<<endl;
 for(i=0;a[i]!='\0';i++)  //printing array on the screen
 cout<<a[i];
 sleep(3);                //paused program for 3 second
}

answered Dec 13 '14 at 07:22

tubbystubby

21
1

`getch()`takes the key which you press on the keyboard but doesn't print anything on screen, so we print a '*'-using `printf("*")` instead of the character user enters, if user press's enter(13-is ascii code for enter) the loop breaks and line-`a[i]='\0'`, puts a null character at end of the array.`sleep(3)` delays program termination by three second. – tubbystubby Dec 13 '14 at 07:31

How do I display star(*) instead of plain text for password c++

3 Answers3