Member function definition outside of class

Question

Is it possible to define function or method outside class declaration? Such as:

class A 
{
    int foo;
    A (): foo (10) {}
}

int A::bar () 
{
    return          


        

Answer 1

You can define a method outside of your class

// A.h
#pragma once
class A 
{
public:
    A (): foo (10) {}
    int bar();
private:
    int foo;
};

// A.cpp
int A::bar () 
{
    return foo;
}

But you cannot declare a method outside of your class. The declaration must at least be within the class, even if the definition comes later. This is a common way to split up the declarations in *.h files and implementations in *.cpp files.