funct,classes,pointer,selection_operator

// Let's create a sample function called myPrint() in our class. 
/*  methods are functions. 
It was declared initially in myClass() and later defined in myClass::myClass() {} 
MyClass.h
*/

class MyClass
{
  public:
   MyClass();
   void myPrint();
};

// MyClass.cpp
#include "MyClass.h"
#include <iostream>
using namespace std;

MyClass::MyClass() {
}

void MyClass::myPrint() {
  cout <<"Hello"<<endl;
}
// Since myPrint() is a regular member function, it's necessary to specify its return type in both the declaration and the definition.

// prototype the myPrint function in Sally class declaration


class  Sally {
public :
 Sally();
 void myPrint ();
};

// object of the type MyClass, and call its myPrint() function using the dot (.) operator:

#include "MyClass.h"

int main() {
  MyClass obj;
  obj.myPrint();
}

// Outputs "Hello"

// Drag and drop from the options below to declare an object of class Sally in the main function, and call its myPrint member function using the . (dot) operator.

int main() {
 Sally  obj;
 obj.myPrint() ;
}

/* Pointers
We can also use a pointer to access the object's members. 
The following pointer points to the obj object:
The type of the pointer is MyClass*, as it points to an object of that type.
*/
MyClass obj;
MyClass *ptr = &obj;

//  a pointer to ''obj'':
Sally obj;
Sally *sallyPtr = &obj;

// Selection Operator
// The arrow member selection operator (->) is used to access an object's members with a pointer.
/* When working with an object, use the dot member selection operator (.).
When working with a pointer to the object, use the arrow member selection operator (->).
*/

MyClass obj;
MyClass *ptr = &obj;
ptr->myPrint();

// ptr->myPrint() is equivalent to (*ptr).myPrint()

In words: Get me the target of ptr and call its myPrint() method.

/*
there are 3 ways to access object methods :
object methods, pointer selector, pointer dereference. 
see example below :
*/

#include <iostream>
using namespace std;

class MyClass
{
    public:
        MyClass();
        void myPrint();
};

MyClass::MyClass() {
}
void MyClass::myPrint() {
    cout <<"Hello"<<endl;
}
// three ways to object methods
int main() {
    MyClass obj;
    // 1st way object methods  
    obj.myPrint();
    
    MyClass *ptr = &obj;
    // 2nd way using pointer selector
    ptr->myPrint();
    // 3rd way using pointer dereference
    (*ptr).myPrint();
}

// You can access an object's members in these 5 possible ways:

//1
MyClass obj;
obj.myPrint();

//2
MyClass obj;
MyClass *ptr = &obj;
ptr->myPrint();

//3
MyClass obj;
MyClass *ptr = &obj;
(*ptr).myPrint();

//4
MyClass obj;
MyClass &ptr = obj;
ptr.myPrint();

//5
MyClass obj;
MyClass &ptr(obj);
ptr.myPrint();

⚠️️Important Operators⚠️    
-------------------------------------------

1)   ::    Scope operator
- Useful for calling functions of a class from source file
- Type ClassName::FunctionName()


2)   .     Dot operator
- Useful for calling different methods of an object (methods could be variables or functions of a class)
- Type Obj.MethodName();


3)   ->   Selection operator
- Useful for calling different methods of an object by a pointer to the object.
- PointerName->MethodName();