Question

There is an error when i try to compile and im not sure whats wrong with it.
This is a program which authencate username and password with textfile, seperated with “;” delimeter in a single textfile.
The error is quite long.

/tmp/ccgs7RYV.o: In function 'Employee::Employee()':
main2.cpp:(.text+0xa5): undefined reference to 'Employee::authenticate(std::basic_string, std::allocator>, std::basic_string, std::allocator>)'
/tmp/ccgs7RYV.o: In function `Employee::Employee()':
main2.cpp:(.text+0x231): undefined reference to 'Employee::authenticate(std::basic_string, std::allocator>, std::basic_string, std::allocator>)'
collect2: ld returned 1 exit status

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

using namespace std;

class Employee
{
public:
Employee();
bool authenticate(string, string);
};

Employee::Employee()
{
    string username, password;
    cout << "Username: ";
    cin >> username;

    cout << "Password: ";
    cin >> password;

    if (authenticate(username, password) == true)
        cout << "Sucess" << endl;
    else
        cout << "fail" << endl; 
}

bool authenticate(string username, string password) 
{
    std::ifstream file("login.txt");
    std::string fusername, fpassword;

    while (!file.fail()) 
    {
        std::getline(file, fusername, ';'); // use ; as delimiter
        std::getline(file, fpassword); // use line end as delimiter
        // remember - delimiter readed from input but not added to output

        if (fusername == username && fpassword == password)
            return true;
    }

    return false;
}


int main()
{
    Employee();
    return 0;
}

Answer 1

bool Employee::authenticate(string username, string password) {
std::ifstream file("login.txt");
std::string fusername, fpassword;

while (!file.fail()) {
    std::getline(file, fusername, ';'); // use ; as delimiter
    std::getline(file, fpassword); // use line end as delimiter
    // remember - delimiter readed from input but not added to output
    if (fusername == username && fpassword == password)
        return true;
}

You need to use the scope resolution operator. You were just missing that.