How to call Objective-C method from C++

I know the way of calling Objective-C method from C++ file without connecting file for them. Check this below and you will notice how easy it is. Also, this is available for Cocos2d-x project.

Files

SubView.h (A header file for getting call)
// The class from C++ call
class SubView
{
    public:
        // Getting call from C++
        static void callObjC();
};

SubView.mm (A source file for getting call)
#import "SubView.h"

// Not in header file.
@interface ClassObjC : NSObject

+ (void)testingMethod;

@end

// Objective-C class in source file as normal way
@implementation ClassObjC

//--------------------------------------------------
// [Objective-C] for testing
//--------------------------------------------------
+ (void)testingMethod
{
    NSLog(@"I was called from C++");
}

@end

//==================================================
// [C++] Call the method of Objective-C class
//==================================================
void SubView::callObjC()
{
    [ClassObjC testingMethod];
}

MainView.cpp (For calling Objective-C)
#include "SubView.h"

void MainView::mainFunc()
{
    SubView::callObjC();
}

Short Description

This is like portal for C++ in Objective-C file.
The number of functions is here.
  1. MainView::mainFunc()
  2. SubView::callObjC()
  3. [ClassObjC testingMethod]
Such as, if your project has Objective-C file, replace the class interface to the source file from the header file, and just add the C++ coding then done. Also remind this file extension need to be ".mm".