Question

In C++, i have:

//Base1.h
#ifndef BASE1_H
#define BASE1_H
#include <iostream>
#include <string>
#include "Base2.h"

using namespace std;

class Base1{
    private:
        string name;
    public:
        Base1(string _name);
        void printSomething();
        string getName();
};
#endif

In Base1.cpp i implement constructor Base1(string _name) and string getName() as normal, and the printSomething():

void Base1::printSomething(){
    Base2 b2;
    // how to pass a parameter in the following code?
    b2.printBase1();
}

// This is Base2.h
#ifndef BASE2_H
#define BASE2_H

#include <iostream>
#include <string>
#include "Base1.h"

using namespace std;

class Base2{
    public:
      Base2();
      void printBase1(Base1 b);
};
#endif

And Base2() constructor i implement as usual, this is my printBase1(Base1 b):

void Base2::printBase1(Base1 b){
    cout << b.getName();
}

So, in the end, i want to use printSomething() in Base1 class, but i don’t know how to pass parameter to the b2.printBase1() in printSomething() as above in my code. is there anything like b2.printBase1(this) in C++? If not, can you give me a suggestion?

Answer 1

Since this is a pointer in C++, you need to dereference it:

b2.printBase1(*this);

Note that you have circular includes, you should remove #include "Base2.h" from Base1.h. Also look into passing parameters by (const) reference, especially for non-POD types, otherwise you might not get the expected behavior.

For example, your signature is

void printBase1(Base1 b);

when you call it, you create a copy of the parameter in the function, and thus operating on a copy. You should change this to:

void printBase1(Base1& b);

or

void printBase1(const Base1& b); //if you don't change b

Pass by value only when you’re certain you need a copy.