How can I make backspace not count as a character? - c++

Question

So, I have to encrypt my console application with a password, i did something that's working but there is a problem, backsapce doesn't erase the character entered, it is also counted as a character, how can I make it to do its job, to erase the character?
This is the code:
void main()
{
char password[20], my_password[20] = "password";
int i;
char ch;
system("cls");
cout << "PASSWORD: ";
i = 0;
do
{
ch = _getch();
password[i] = ch;
if (ch != 27 && ch != 13 && ch != 9)
cout<<"*";
else
break;
i++;
} while (i < 19);
password[i] = '\0';
if (strcmp(password, my_password) != 0)
{
cout << "\n\nIncorrect password !!!";
cin.get();
return;
}
cout << "\n\nPassword is correct !";
cout <<"\n\nThe program is executed !";
cin.get();
}

Answer 1

void main()
{
char password[20], my_password[20] = "password";
int i;
char ch;
system("cls");
cout << "PASSWORD: ";
i = 0;
do
{
ch = _getch();
if (ch == 8)
{
i--;
cout << "\b \b";
continue;
}
password[i] = ch;
if (ch != 27 && ch != 13 && ch != 9)
cout << "*";
else
break;
i++;
} while (i < 19);
password[i] = '\0';
if (strcmp(password, my_password) != 0)
{
cout << "\n\nIncorrect password !!!";
cin.get();
return;
}
cout << "\n\nPassword is correct !";
cout << "\n\nThe program is executed !";
cin.get();
}
Not the cleanest code but it works. Decrement the counter to over write the previous character and output two backspace characters separated by a space.

Answer 2

"how can I make it to do its job, to erase the character?"
Use a curses library. Like ncurses.

Answer 3

You could check if the character received is a backspace, if it is decrement i which will effectively remove the last character.
i = 0;
do
{
ch = _getch(); // get the character
if(ch == DEL || ch == BS) // check for backspace
{
i--;
cout << BS;
}
else if(ch >= ' ' && ch <= '~') // check if its valid ASCII
{
password[i] = ch;
cout << "*";
i++;
}
else if (ch == 27 || ch == 13 || ch == 9) // check if entry is complete
{
break;
}
} while (i < 19);
password[i] = '\0';
somewhere else
#define BS '\b'
#define DEL 127