constructors and destructors

A constructor is a method that gets called immediately when an object is allocated (on the stack or the heap).
It is the constructor’s job to initialize the object’s attributes to sensible initial values.
A constructor may have parameters that can inform the initial values. A constructor has the same name as the class.
You can have more than one constructor.
A constructor has no return type and no return statement.
C++ gives every class a default (implicit) constructor that takes no arguments, and does nothing.




A destructor is a method that gets called immediately when an object is de-allocated.
It is the destructor’s job tidy up. It may need to deallocate memory on the heap, or close a file.
A destructor may not have parameters.
A destructor has the same name as the class, preceded with a “∼”. You can have only one constructor.
A constructor has no return type and no return statement.

C++ gives every class a default (implicit) destructor that does nothing.



class Point 

// sample class private:
float x; // stores the x coordinate 
float y; // stores the y coordinate
public:
Point(); //the constructor 
void setX(float newX); 
void setY(float newY); 
float getX();
float getY();
~Point(); //the destructor
};


Point::Point()
{
x = 0;
y = 0;
}






Point::~Point()

//do nothing
}

原文地址:https://www.cnblogs.com/liguangsunls/p/7280086.html