Login Function??

im getting an error with this piece of code, im sure theres a better way to do it but hey its my first shot at it;

Code:

string Login()
{//function
     
     int x,i,y;
     char Buffer[50], Buffer2[50], Username[50], Password[50];          
     char ch = getch();
     
    do
    {
        system("cls");
                      
        cout << "Login" << endl
             << endl;                                   
             
        cout << "Username       : ";
        cin.getline(Username, 50, '\n');    
        
        cout << endl;           
        cout << "Password       : ";
            
            while (ch != '\r')
            {//while                                                                      
                  i=0;                 
                  ch = getch();
                  Password[i] = ch;   //small loop so only * are displayed instead of actual password
                  cout << '*';
                  i++;
            }//while
            
     ifstream SAM_File("C:\\Documents and Settings\\Dean.Downstairs\\My Documents\\OperationalFiles\\SAMFile.dat");     
     SAM_File.getline(Buffer, 50);
     
     for(x=0; x<50; x++)
     {             
             SAM_File.getline(Buffer[x],x);  //gets set username from .dat file
     }
     
     
     for(y=0; y<50; y++)
     {
              SAM_File.getline(Buffer[y],y);  //gets set password from .dat file
     }
                       
     SAM_File.close();
         
     ch = ' ';         //sets to 0 so its not full
     
     } while(Buffer != Username || Buffer2 != Password);
                 
};//function

thanks for help in advance,

o ye, heres the errors;

F:\Computing Coursework\Computing Coursework.cpp In function `std::string Login()':

893 F:\Computing Coursework\Computing Coursework.cpp invalid conversion from `char' to `char*'

893 F:\Computing Coursework\Computing Coursework.cpp initializing argument 1 of `std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::getline(_CharT*, std::streamsize) [with _CharT = char, _Traits = std::char_traits<char>]'

899 F:\Computing Coursework\Computing Coursework.cpp invalid conversion from `char' to `char*'

899 F:\Computing Coursework\Computing Coursework.cpp initializing argument 1 of `std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::getline(_CharT*, std::streamsize) [with _CharT = char, _Traits = std::char_traits<char>]'

getline() needs a char* and not a char.

This is what you may want to do:

SAM_File.getline(Buffer, 50);

Besides, remember that you cannot compare C-style strings with the != operator. Either use std::string or use the strcmp() function.

Edit: You also declare the function as returning a string, yet you never use strings anywhere in your code nor do you return anything at all. You also end your function with a semi-colon which is not necessary. It is only necessary to put a semi-colon after a closing brace when declaring a struct or a class and maybe an enum too (not sure about this one).

and password should be read into Buffer2 not Buffer

Originally Posted by Desolation

getline() needs a char* and not a char.

This is what you may want to do:

SAM_File.getline(Buffer, 50);

Besides, remember that you cannot compare C-style strings with the != operator. Either use std::string or use the strcmp() function.

Edit: You also declare the function as returning a string, yet you never use strings anywhere in your code nor do you return anything at all. You also end your function with a semi-colon which is not necessary. It is only necessary to put a semi-colon after a closing brace when declaring a struct or a class and maybe an enum too (not sure about this one).

thanks, lol, ive been trying it every which way but loose, and i was editing it all the time. it was using strings before,

ok its still not working, a little fine tuning needed i think;

edit: it just breaks from the loop every time, even when the password or username is wrong.

Code:

void Login()
{//function     
     int i;
     char Buffer[50], Buffer2[50], Username[50], Password[50];          
     char ch = getch();
     
    do
    {
        system("cls");
                      
        cout << "Login" << endl
             << endl;                                   
             
        cout << "Username       : ";
        cin.getline(Username, 50, '\n');    
        
        cout << endl;           
        cout << "Password       : ";
            
            while (ch != '\r')
            {//while                                                                      
                  i=0;                 
                  ch = getch();
                  Password[i] = ch;
                  cout << '*';
                  i++;
            }//while
            
     ifstream SAM_File("C:\\Documents and Settings\\Dean.Downstairs\\My Documents\\OperationalFiles\\SAMFile.dat");     
     SAM_File.getline(Buffer, 50);    
     
     SAM_File.getline(Buffer, 50);     
     SAM_File.getline(Buffer2, 50);  
      
     SAM_File.close();
     
     ch = ' ';
     
     } while(strcmp(Username, Buffer) == 0 || strcmp(Password, Buffer2) == 0);                 
}//function

Use C++ (or std: strings. It makes comparison much easier! You can use the == operator. #include <string>.

Originally Posted by twomers

Use C++ (or std: strings. It makes comparison much easier! You can use the == operator. #include <string>.

im not familiar with std::, could you give me an example please.

Sure.

Code:

#include <iostream>
#include <fstream>
#include <string>

#include <windows.h>
#include <conio.h>

using namespace std;

int main( void )
{
    string Buffer   ="USERNAME", 
            Buffer2  ="PASSWORD", 
            Username ="", 
            Password =""; // No harm in initialising things!

     
    do
    {
		cout<< "Enter your username: ";
		getline( cin, Username ); // Defaults to termination at '\n'

		cout<< "Enter your password: ";
		getline( cin, Password );
     
     } while(Username!=Buffer && Password != Buffer2 );    

	return 0;
}

They're just C++ style strings as opposed to character arrays. Lots of functionality and it's no harm in getting to know them!

Originally Posted by twomers

Sure.

Code:

#include <iostream>
#include <fstream>
#include <string>

#include <windows.h>
#include <conio.h>

using namespace std;

int main( void )
{
    string Buffer   ="USERNAME", 
            Buffer2  ="PASSWORD", 
            Username ="", 
            Password =""; // No harm in initialising things!

     
    do
    {
		cout<< "Enter your username: ";
		getline( cin, Username ); // Defaults to termination at '\n'

		cout<< "Enter your password: ";
		getline( cin, Password );
     
     } while(Username!=Buffer && Password != Buffer2 );    

	return 0;
}

your missing the entire idea behind the function lol, its not supposed to display the password on entry, just *'s.

I was leaving that to you

ok, this function is giving me great grief, its just not playing ball in any way. it just continues to loop even when the condition is 0.

here it is;

Code:

void Login()
{//function     
             
     char ch = getch();
     string Buffer, Buffer2, Username, Password;
     
    do
    {
        system("cls");
                      
        Username = "";
        Password = "";
        
        cout << "Login" << endl
             << endl;                                   
             
        cout << "Username         : ";
        getline(cin, Username);     
        
        cout << endl;           
        cout << "Password         : ";
            
            do
            {//while                                                                      
                                  
                  ch = getch();
                  
                  Password += ch;
                 
                 if(ch == '\r')
                 {
                       break;
                 }
                 else if(ch != '\r')
                 {
                  cout << "*";
                 }
                  
            }while (ch != '\r');
                       
      Username = "Dcarr";
      Password = "shadow";
   
     } while(Username != Buffer || Password != Buffer2); 
                    
}//function

Here's some code for ya:

Code:

#include <iostream>
#include <fstream>
#include <string>

#include <windows.h>
#include <conio.h>

using namespace std;

bool Login()
{//function     
             
	char ch;
	string u_buf, p_buf, Username, Password;
//	Set the values of u_buf and p_buf here. Shouldn't really hard code them in

	system("cls");
//	there's a better alternative to this in the FAQ
	   

	cout	<< "Login" << endl
		<< endl;                                   

	cout << "Username         : ";
	getline(cin, Username);     

	cout << endl;           
	cout << "Password         : ";

	while ( ch != '\r' )
	{ 
		ch = getch();

		if ( ch!='\r' )
		{
			Password += ch;
			cout << "*";
		}
	}


	return Username == u_buf && Password == p_buf;
                    
}//function

int main( void )
{
	if ( Login() == true ) // could change to: if ( Login ){...} as the function will return true or false
		cout<< "Welcome!";
	else 
		cout<< "Try again";

	return 0;
}

I changed a couple of things around. I made the function a bool so that you could test for equality in main(). If you want to loop it, just do a while(Login()==false); (or while( !Login() ); and it should do the same as your original code.

Here is a variant of twomers' code example that incorporates some support for backspaces. Not guaranteed to work, I just happened to be intrigued by the idea as I rarely work with getch().

Code:

#include <iostream>
#include <cstdlib>
#include <string>

#include <conio.h>

using namespace std;

// Returns true if login was successful.
bool Login()
{
    // Set the values of u_buf and p_buf here.
    // There may be alternatives to hardcoding them in.
    string u_buf("user"), p_buf("pass");

    system("cls"); // There is a better alternative to this in the FAQ.

    cout << "Login\n" << endl;

    string Username;
    cout << "Username         : ";
    getline(cin, Username);

    string Password;
    cout << "Password         : ";
    // read input until a newline sequence is encountered
    for (;;)
    {
        char ch = getch();

        if (ch == '\r' || ch == '\n')
        {
            break;
        }
        else if (ch == 8)
        {
            // handle backspace by erasing what is printed
            if (!Password.empty())
            {
                // we have to erase from the string too
                Password.erase(Password.end() - 1);
                cout << char(8) << " " << char(8);
            }
        }
        else
        {
            // not a newline sequence or backspace, so append it
            Password.push_back(ch);
            cout << "*";
        }
    }

    cout << endl;

    return Username == u_buf && Password == p_buf;
}

int main()
{
    if (Login())
    {
        cout << "Welcome!";
    }
    else
    {
        cout << "Try again";
    }
    cout << endl;
    return 0;
}

thanks twormers, :-) :-)