c++中简单的虚函数，和静态方法变量

#include<stdio.h>
#include<stdlib.h>//for malloc
#include<string.h>//for memset
#include<unistd.h>
#include<sys/types.h>
#include<stdint.h>
#include<iostream>

using namespace std;

class base
{
    private:
        int a;
        int b;
    public:
        void show(int c,int d);
        virtual void show1(int c,int d);
        void show2(void);
        base(int a,int b);
        base(){a=1;b=2;cout<<"hello"<<endl;};//无参数构造方法
        virtual ~base();//定义为虚函数，析构时先掉子类的析构，再调父类的析构
    static void show3(int a,int b);
    static int c;//这里只是声明并无空间
};

void base::show3(int a,int b)
{
    cout<<"this is show 3 a is "<<a<<"b is"<<b<<endl;
}

void base::show2(void)
{
    cout<<"this is show2 in base!"<<endl;
    base::c=123;
}

base::base(int a,int b)
{
    cout<<"base int a int b"<<endl;
    this->a=a;
    this->b=b;
}
/*
base::base()
{
    cout<<"base no base"<<endl;
}
*/
void base::show(int c,int d)
{
    cout <<"c is"<<c<<"d is"<<d << endl;
}

void base::show1(int c,int d)
{
    cout <<"virtual method c is"<<a<<"d is"<<b<<endl;
}

base::~base()
{
    cout<<"break base"<<endl;
}

class child :public base
{
    private:
        int a,b;
    public:
        void show(int c,int d);
        virtual void show1(int c,int d);
        child(int a,int b);
        ~child();
};


child::child(int a,int b)
{
    this->a=111;
    this->b=222;
}



void child::show(int c,int d)
{
    cout <<"c is"<<c<<"d is"<<d << endl;
}

void child::show1(int c,int d)
{
    cout<<"this is child virtual method c is"<<this->a<<"d is "<<this->b<<endl;
}

child::~child()
{
    cout<<"break child!"<<endl;
}


int base::c;
int main()
{
    //base *mybase=new base(4,5);
    base *myNew=new child(1,2);
    myNew->show(3,4);
    myNew->show1(3,4);
    myNew->show2();
    base::show3(123,456);
//    base::c=4;
    cout<<"base c is "<<base::c<<endl;
    delete(myNew);
    //delete(mybase);
}