I have a class which has many small functions. By small functions, I mean functions that doesn't do any processing but just return a literal value. Something like:

```
string Foo::method() const{
    return "A";
}

```

I have created a header file "Foo.h" and source file "Foo.cpp". But since the function is very small, I am thinking about putting it in the header file itself. I have the following questions:

1. Is there any performance or other issues if I put these function definition in header file? I will have many functions like this.
2. My understanding is when the compilation is done, compiler will expand the header file and place it where it is included. Is that correct?