C++ Class 方法定义语法

Question

In C++, it is sometimes considered good practice to declare your classes in a header file and define all the methods in a cpp file. I understand this, but a consequence of this seems to be that instead of having all of the class methods tabbed-in inside curly braces, they are just out in the open in the cpp file. Is there any way to group the methods of a class together in the cpp file while still declaring them in a header file? I like being able to collapse things in my IDE... I'd just get over it, but it's been a while since I've coded anything in C++ and I'm wondering if there's a way to do it that I just forgot about.

To be clear what I mean, here's an example:

test.h:

class Testing {
public:
    Testing(int x);
    void print();
    int x;
};

test.cpp:

#include <iostream>
#include "test.h"

using namespace std;

// class Testing {
// public:
//     Testing(int x){
//         this->x = x;
//     }

//     void print(){
//         cout << this->x << endl;
//     }
// };

Testing::Testing(int x){
    this-> x = x;
}

void Testing::print(){
    cout << this->x;
}

int main(){
    Testing t(100);
    t.print();
}

I'd like to do what is commented above in test.cpp instead, but that doesn't work, right? (I think it'd be like declaring a new class distinct from the one in the header file?)

Answer 1

You could do this:

== hh ==

namespace H_DEFS {
    class H {
    public:
       int A();
       int B();
    };
}
using namespace H_DEFS;

== h.cpp file ==

#include "h.h"
namespace H_DEFS {
   int H::A() { return 4;};
   int H::B() { return 5;};
}

== main.cpp ==

#include "h.h"
int main() {
   return H().A() + H().B();
}

but it's a weird idiom for other programmers to read just for the benefit of your IDE.