C++ .h and .cpp file separate - c++

Question

I'm trying to separate my c++ code to one header and one cpp file, but the interpreter showing some errors.
Here is my code:
Password.h:
#ifndef PASSWORD_H
#define PASSWORD_H
class Password {
private:
string aliasName_;
int hashOfPassword_;
public:
void setAliasName(string aliasName);
void setHashOfPassword(int hashOfPassword);
string getAliasName() { return aliasName_; }
int getHashOfPassword() { return hashOfPassword_; }
};
#endif
Password.cpp:
#include <string>
#include "Password.h"
using std::string;
void Password::setAliasName(string aliasName) {
aliasName_ = aliasName;
}
void Password::setHashOfPassword(int hashOfPassword) {
hashOfPassword_ = hashOfPassword;
}
Errors:
Error C2065 'aliasName_': undeclared identifier X\password.cpp 7
Error C2511 'void Password::setAliasName(std::string)': overloaded member function not found in 'Password' X\password.cpp 6
Error C3646 'aliasName_': unknown override specifier X\password.h 6
Error C4430 missing type specifier - int assumed. Note: C++ does not support default-int X\password.h 6
Error C2061 syntax error: identifier 'string' X\password.h 9
Error C3646 'getAliasName': unknown override specifier X\password.h 11
Error C2059 syntax error: '(' X\password.h 11
Error C2334 unexpected token(s) preceding '{'; skipping apparent function body X\password.h 11
Anyone have any ideas ?

Answer 1

You need to move using std::string before the declaration of your class:
#ifndef PASSWORD_H
#define PASSWORD_H
#include <string>
using std::string;
class Password {
…
and remove it from your .cpp file.
Also, you might want to use #pragma once instead of the traditional #ifndef/#define/#endif and finally you might want to make your argument and methods const when need be.

Answer 2

You need to move
#include <string>
using std::string;
To inside Password.h, you can then remove these two lines from Password.cpp.

Answer 3

Just add std:: to every string in your header file and remember, you should never use using or using namespace there! You should also include all the headers to the file in which you use them.