Question

C++ Language

Create Login Register program without open .txt file
simple program also if you can hide password input
option menu
1) Login
2) Register
3) exit

Answer 1

/* Following code is for changing the input visibility for windows nd linux*/

// checks if its windows or linux
#ifdef WIN32
// if windows then include windows.h header file
#include <windows.h>
#else
// if not windows then include following for unix type os
#include <termios.h>
#include <unistd.h>
#endif

// changes the visibility,if true then visible 
void ChangeInputVisibility(bool show = true)
{
// if windows    
#ifdef WIN32
    // get console handler
    HANDLE stdinHandler = GetStdHandle(STD_INPUT_HANDLE); 
    // stores echoinput env variable dword
    DWORD currentMode;
    GetConsoleMode(stdinHandler, &currentMode);
    // changes consolemode ECHO to show/hide inputs
    if( !show )
        currentMode &= ~ENABLE_ECHO_INPUT;
    else
        currentMode |= ENABLE_ECHO_INPUT;

    // sets the new stdinHandler mode
    SetConsoleMode(stdinHandler, currentMode);

#else
    // changes tty ECHO to show/hide inputs
    struct termios tty;
    tcgetattr(STDIN_FILENO, &tty);
    if( !show )
        tty.c_lflag &= ~ECHO;
    else
        tty.c_lflag |= ECHO;

    (void) tcsetattr(STDIN_FILENO, TCSANOW, &tty);
#endif
}

/* following is the basic code*/

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

int main(){
    // stores user's selectio
    int option;

    // holds username , password, current password 
    string userName="",password,loginPassword;

    // repeats untill user seletcs exit
    while(true){

        // show menu
        cout << "\n\noption menu" << endl;
        cout << "1) Login" << endl;
        cout << "2) Register " << endl;
        cout << "3) exit" << endl;
        cout << "select an option: ";

        // gets option
        cin >> option;
        switch(option){
            // for option 1
            case 1:

            // if there is already user registered ask password
            if(userName!=""){
                // asks password
                cout << "Enter password: ";
                // hide inputs
                ChangeInputVisibility(false);
                cin >> loginPassword;

                // show inputs
                ChangeInputVisibility(true);

                // if its correct password,then show username
                if(password==loginPassword){
                    cout << "Logged in as " << userName;
                }else{
                    // else invalid password
                    cout << "Password invalid" << endl;
                }
            }else{
                // if there is no existing user name
                cout << "No account registered" << endl;
            }
            break;
            // if user select option 2
            case 2:
            // ask user name and password
            cout << "Enter username: ";
            cin >> userName;
            cout << "Enter password: ";

            // hide inputs
            ChangeInputVisibility(false);
            cin >> password;

            // show inputs
            ChangeInputVisibility(true);
            break;

            // if user select 3
            case 3:

            // exit the programm
            return 0;
            break;

            // for all other inputs,show invalid option
            default:
            cout << "Invalid input!" << endl;
        }
    }
    return 0;
}

Code screenshot:

Output:

PS: If you have any doubts/problems please comment here.Thank You