C++ :: Creating Login (username And Password)

I am trying to create a login that accepts a user login and password. it should accept 3 tries in which when the user enters their username the system should tell whether if the username is correct if not it should display a message saying invalid username and directs the user to register like entering their dob and name. But I cannot seem to get this part run correctly.

#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
#include<string.h>
void main() {
char userId[10];
char passwrd[10];
int p = 0;

[Code] .....