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

Answer 1

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;
}