C + + class Basic Syntax example Analysis _c language

Class is a very important concept of C + + programming, and this article illustrates the common usage of classes in instance form. Specifically as follows:

This test code mainly includes the following content:

(1) How to use the constructor function;
(2) default constructor;
(3) Assigning values between objects;
(4) const use of grammar;
(5) Defining class constants: One method is to use an enum, and the other is to use static.

The instance code is as follows:

#include <iostream> using namespace std;

Enum Sextype {man, WOMAN};
    Class Human {//the default is private private:string name;
    Sextype sex;

    int age;
    (5) Defining class constants: One method is to use an enum, and the other is to use static enum{len=1};

  static const int LEN2 = 3; Public://If no constructors are provided in the class definition, the compiler provides a default constructor.
    However, if a constructor is defined in a class, the writer must provide a default constructor at the same time.
    There are two ways to provide a default constructor://(1) to define a constructor with no parameters: Human ();
    (2) Provide a default value for a parameter that is not a default constructor: Human (String m_name= "No Name", int m_age=0, Sextype m_sex=man);
    Two definitions can only be two selected Human ();
    Human (string m_name, int m_age, Sextype m_sex);
    Human (int m_age);

    ~human (); The method defined in the class declaration is an inline method.
    You can also use the inline keyword to define a function outside of a class declaration.
    The Void Show () const//const is added after the function name to indicate that the function does not modify the data members of the class. {cout<< ' This is ' <<name<< ', Sex: ' <<sex<< ', ' <<age<< ' Years old.
    <<endl;

}
};

Human::human () {cout<< "default construct function" <<endl;}
Human::human (string m_name, int m_age, Sextype m_sex) {  cout<< "construct function:" <<m_name<<endl;
  name = M_name;
  age = M_age;
sex = M_sex;

} human::human (int m_age) {age = M_age;}

Human::~human () {cout<< "destroy function:" <<name<<endl;}
  int main () {cout << "This is test code of C + + class:" << Endl;    {//(1) Use of construct function Human Jack = Human ("Jack");//Show Call Human Jerry ("Jerry", Num, man); Implicit invocation of Human *ptom = new Human ("Tom", man); The new call//When the constructor has only one argument, you can assign the value directly with the assignment statement. The constructor of only one parameter will be automatically invoked Human marry = 11;

    Assignment Call//(2) Defaults construct function Human Lucy;
    (3) Assignment Object Human James; James = Human ("James", man); Create a temporary object james,copy a portion of this object is assigned to the James variable.

    The temporary object will be destroyed immediately thereafter.
    (4) Const const Human Thomas ("Thomas", man); Thomas.show ();
The Show method must define with ' const '} return 0;
 }

The result of the program running is: