C/c++:c++ how to construct a parent class

C + + Executes the construction method of the parent class. This is written on the basis of the inheritance of the original class.

First, we create a project. Then build our parent class.

People.h:

<span style= "FONT-SIZE:18PX;" > #ifndef people_h#define people_h#include<iostream>using namespace Std;class people{public    :        People ();//people default constructor method        people (int age, int sex);//Constructs a method without returning the type        int get_age ();//Get ages        int get_sex ();// Get gender    private:        int age;        int sex;//Specify 1 for male, 0 for female;}; #endif//People_h</span>

Then we have a CPP file in our parent class to specifically write our construction method:

<span style= "FONT-SIZE:18PX;" > #include "People.h" People::P eople () {This--age    =;    This, sex = 1;} People::P eople (int age, int sex) {This--age    = age;    This, sex = sex;} Constructs a method without returning the type int people::get_age () {return this--age    ;} int People::get_sex () {    return this, sex;} </span>

Well, the parent class is ready, and we'll create a subclass:

<span style= "FONT-SIZE:18PX;" > #ifndef main_h#define main_h#include "People.h" class Main:public people{public    :    private:};//Inherits parent class people #endif//Main_h</span>

In this way our subclass inherits the parent class people.

Then, it's our main file:

<span style= "FONT-SIZE:18PX;" > #include "Main.h" int main () {    main *p = new Main ();    cout << p->get_age () << Endl;    cout << p->get_sex () << Endl;    Delete p;    return 0;} </span>

Now it's ready to run.

And the result is 18 and 1; Why is this result? Because, now our subclass main just inherits the People class,

Did not write its own construction method, the data passed to a parent class. That is, the default constructor that executes the people class.

Good. Now, let's write the subclass main's constructor method to pass in the data to the parent class;

Main.h:

<span style= "FONT-SIZE:18PX;" > #ifndef main_h#define main_h#include "People.h" class Main:public people{public    :        MAIN (int age, int sex);};/ /Inherit parent class People#endif//Main_h</span>

now that the subclass constructor is written, how do we do it to pass the data to the parent class?

<span style= "FONT-SIZE:18PX;" > #include "Main.h" main::main (int age, int sex):P eople (age, Sex) {}</span>

is to use ":" this. To pass the data of the constructed method in our subclass back to the parent class.

OK, let's change the main function to see the effect:

<span style= "FONT-SIZE:18PX;" > #include "Main.h" int Main () {    int a = +;    int b = 0;    Main *p = new Main (a, b);    cout << p->get_age () << Endl;    cout << p->get_sex () << Endl;    Delete p;    return 0;} </span>

At this point, we are outputting the result is 16 and 0.

PS: One small step per day.

C/c++:c++ how to construct a parent class