C Program to Input Password for Validation of User name

How to Input Password in C ?

#include< stdio.h>
#include< conio.h>

void main()
{
char password[25],ch;
int i;

clrscr();
puts("Enter password : ");

while(1)
    {
    if(i<0)
         i=0;
    ch=getch();

    if(ch==13)
        break;

    if(ch==8) /*ASCII value of BACKSPACE*/
        {
        putch('b');
        putch(NULL);
        putch('b');
        i--;
        continue;
        }

   password[i++]=ch;
   ch='*';
   putch(ch);
   }

password[i]='';
printf("\nPassword Entered : %s",password);
getch();
}

Output :

Enter password : ******
Password Entered : rakesh

---

Explain ?

ch=getch();

• Accept Character without Echo [ without displaying on Screen ]
• getch will accept character and store it in “ch”

if(ch==13)
        break;

• ASCII Value of “Enter Key” is 13
• Stop Accepting Password Characters after “Enter” Key.

if(ch==8) /*ASCII value of BACKSPACE*/
        {
        putch('b');
        putch(NULL);
        putch('b');
        i--;
        continue;
        }

• ASCII Value of “BACKSPACE” is 8
• After hitting “backspace”following actions should be carried out -
  • Cursor Should be moved 1 character back.
  • Overwrite that character by “NULL”.
  • After Writing NULL again cursor is moved 1 character ahead so again move cursor 1 character back .
  • Decrement Current Track of Character. [i]

password[i++]=ch;
   ch='*';

• Store Accepted Character in String array .
• Instead of Displaying Character , display Asterisk (*)