szstock(int a,int b):stock(a){z=b;}这行代码什么意思？

Question

# include < iostream>

using namespace std;

class stock

{

public :

stock(){x = 0;}

stock(int a){x = a;}

virtual void display()=0;

int getx(){ return x;}

private:

int x;

 };

 class shstock : public stock

{

public:

shstock( int a){ y=a;}

 private:

int y;

 };

class szstock : public stock

 {

public:

szstock( int a, int b): stock(a){z=b;}

void display(){

cout << getx()<<" "<z<< endl;

}

private:

  int z;

};

 int main()

{

stock b;

shstock d1(5);/ /compile error

szstock 2(5,б);

//compile error

d2. display();

return 0;

 }

 

Answer 1

szstock( int a, int b): stock(a){z=b;}

子类szstock的构造函数，在构造子类时，先构造基类stock，并将参数a传递给基类构造函数。子类构造函数体内容为将参数b赋值给成员变量z