Overloaded global class functions

[SlimT88]

I recently created a simple class for a homework assignment and ran into compilation errors concerning overloaded global functions. I've copied the relevant parts of my code below and the errors generated on two compilers

Class Definition:

class BDay
 
{      //Should Be Global Scope
      bool operator==( const BDay & , const BDay &);
      bool operator!=( const BDay & , const BDay &); 
      friend ostream & operator<<( ostream &, const BDay &);
 
                  public:
...
...
...
                  private:
...
...
...
}
 
Member Defintion:
 
bool operator!=( const BDay & lhs, const BDay & rhs )
{
     if (lhs.getName() != rhs.getName()|| lhs.getDay() != rhs.getDay()|| 
         lhs.getMonth()!= rhs.getMonth())
         return true;
     else 
         return false;
}
 
bool operator==( const BDay & lhs, const BDay & rhs )
{
     return !(lhs != rhs);
}

Errors Generated:

Bloodshed Dev C++:
28 C:\Dev-Cpp\CS311\bday.h `bool BDay::operator==(const BDay&, const BDay&)' must take exactly one argument
29 C:\Dev-Cpp\CS311\bday.h `bool BDay::operator!=(const BDay&, const BDay&)' must take exactly one argument

In Visual Studio C++ 2008 Express Edition:
1>c:\dev-cpp\cs311\bday.h(29) : error C2804: binary 'operator ==' has too many parameters
1>c:\dev-cpp\cs311\bday.h(30) : error C2804: binary 'operator !=' has too many parameters


It's obvious in the Dev error that the compiler is assuming that the overloaded '!=' and '==' are member functions with one too many parameters though they are declared globally.

Thanks for any help

[Ganon11]

The functions are not declared globally - as you have them right now, they are declared as member functions. When the logical operators are included as part of the class definition, they accept one argument, which is compared to the *this object.

You can declare the functions outside the class body, in which case your current definitions are correct. They must be declared as friend functions inside the class declaration.

[weaknessforcats]

They must be declared as friend functions inside the class declaration.

Only if they need access to class private members. If they can operate by calling other class methods to get the data (preferred), they do not have to be friends.