C++ I want to do something like Class1.Class2.Fct()

Question

I am new to C++ programming and I need your help:

Let's say I have a class - Class1. Is it possible to have another class (Class2) with (at least) one function that returns (for example) an integer? Here is an example with I want to achive:

std::cout << "I did it: " << Class1.Class2.ReturnINTEGER() << std::endl;

I need the code to be compatible with GNU G++ compiler. Thanks :).

I think you need a [good book](http://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list) to get you started on how to do just that. — Rakete1111, Sep 20 '16 at 19:16
You don't put class names before `.`, you put variables whose type is the class. — Barmar, Sep 20 '16 at 19:16
`.` separates a variable (or other expression that returns a struct or class object) from a member name in the class. — Barmar, Sep 20 '16 at 19:17
I think that you might be right, @Rakete1111 - but do you know the answer or anything like this? — VVI C And C 15, Sep 20 '16 at 19:18
@VVICAndC15 Sure, but start to learn classes, and you will see that it is really easy to do that :) — Rakete1111, Sep 20 '16 at 19:20

Seth Kitchen · Answer 1 · 2016-09-20T19:33:07.223

1

#include <iostream>
using namespace std;
class Two
{
public:
    int toReturn;
    Two()
    {
        toReturn=0;
    }

    int returnValue() 
    {
         return toReturn;
    } 
};

class One
{
 public:
     Two foo;
};

int main() 
{
    One bar;
    int toPrint=bar.foo.returnValue();
    cout << toPrint << endl;
}

edited Sep 20 '16 at 19:33

answered Sep 20 '16 at 19:21

Seth Kitchen

1,526
19
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Ok - i tried to solve the errors - here: – VVI C And C 15 Sep 20 '16 at 19:27
#include using namespace std; class Two { public: int toReturn; Two() { toReturn=0; } int returnValue() { return toReturn; } }; class One { public: Two foo; }; int main() { One bar; int toPrint=bar.foo.returnValue(); cout << toPrint << endl; } – VVI C And C 15 Sep 20 '16 at 19:27

score 0 · Accepted Answer · answered Sep 20 '16 at 19:23

0

Yes, it can be done. Let's dissect or rebuild. First to get Class1.Class2, we need to have a class member called Class2. And Class2 needs to have a member called Fct.

Here is one implementation:

struct Class2_Object
{
  void Fct(void);
};

struct Class1_Object
{
  Class2_Object Class2;
};

Class1_Object Class1;
Class1.Class2.Fct();

answered Sep 20 '16 at 19:23

Thomas Matthews

56,849
17
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This one helps - thanks a lot :)) – VVI C And C 15 Sep 20 '16 at 19:29
Please don't use `void` to specify that no arguments should be passed to `Fct`, it is completely unnecessary. – Rakete1111 Sep 20 '16 at 20:08
@Rakete1111: Although unnecessary *in C++*, it is allowable, and a carry over from the C language. I'm presently programming in both languages, but on different projects. – Thomas Matthews Sep 20 '16 at 20:47
@Thomas Yes, but as this is a C++ question, I think it is better to answer in C++, and not in C – Rakete1111 Sep 21 '16 at 05:38

C++ I want to do something like Class1.Class2.Fct()

2 Answers2