Hi, I am making a sign in and sign out code.

#include <iostream>
#include <iomanip>
#include <fstream>
#include <string>
#include<stdlib.h>
#include<time.h>
#include <cstdlib>
#include "conio.h"
using namespace std;
int check(string username)
{
	cin >> username;
	string data1, data2;
	ifstream infile;
	infile.open("profile.txt", ios::app);
	getline(infile, data1);
	if (username == data1)
	{
		cout << "Username exits" << endl;
		cout << "Enter new username: ";
		cin >> username;
		return check(username);
	}
	else
	{
		
	}
}
int main()
{
	int z;
FIRST:	
	cout << "Press 1 to Create Account" << endl; cout << "Press 2 to Log In " << endl; cout << "your choice: ";
VALID:	cin >> z;
	switch (z)
	{
	case 1:                            
	{
		string name, pas, repas;
		cout << "Enter Your username:";
		cin >> name;
		check(name);
	    cout << "Enter Password(Atleast 5 characters) :";
		START1:     cin >> pas;
		if (pas.length() < 5)
		{
		    cout << "Enter a password of atleast 5 characters : ";
			goto START1;
		}
		else
			cout << "Re-write Password to confirm:";
	START2:		cin >> repas;	
		if (repas != pas)
		{
			cout << "Re-Enter the Password !";
			goto START2;
		}
			else
				cout << "Profile Created With the User Name " << name << endl;    // cout on the console
		ofstream myfile;
		myfile.open("profile.txt",ios::app);
		myfile << name << endl;        
		myfile << pas << endl;             
	    myfile.close();
	    _getch();
		system("CLS");
		goto FIRST;   
	}
	case 2:         // For logging in
	{
						system("CLS");
						cout << "Welcome to Login screen\n\m";
						char pass[32];
						string name, pas;
					START3:		
						cout << "Enter Username:";
						cin >> name;
						string data1, data2;
						ifstream infile;
						infile.open("profile.txt",ios::app);
						getline(infile, data1);   
						if (name != data1)
						{
							cout << "Invalid User Name.Try Again\n";
							goto START3;
						}
						else
							cout << "User Name Found\n";
						cout << "Enter Password : ";
						int i = 0;
						char a;
						for (i = 0;;)
						{
							a = _getch();
							if ((a >= 'a'&&a <= 'z') || (a >= 'A'&&a <= 'Z') || (a >= '0'&&a <= '9'))
							{
								pass[i] = a;
								++i;
								cout << "*";
							}
							if (a == '\b'&&i >= 1)
							{
								cout << "\b \b";
								--i;
							}
							if (a == '\r')
							{
								pass[i] = '\0';
								break;
							}
						}
						getline(infile, data2);         
					START4:		if (pass == data2)
					{
									cout << "You are Logged In";
									_getch();
					}
								else
								{
									cout << "Invalid Password\nEnter Again:";
									char pass[32];
									cout << "Enter Password : ";
									int i = 0;
									char a;
									for (i = 0;;)
									{
										a = _getch();
										if ((a >= 'a'&&a <= 'z') || (a >= 'A'&&a <= 'Z') || (a >= '0'&&a <= '9'))
										{
											pass[i] = a;
											++i;
											cout << "*";
										}
										if (a == '\b'&&i >= 1)
										{
											cout << "\b \b";
											--i;
										}
										if (a == '\r')
										{
											pass[i] = '\0';
											break;
										}
									}
									goto START4;
								}

								infile.close();
								break;
	}
	default:

	{ 
			   cout << "Please Enter Valid Number !";
			   goto VALID; }
	}
}