这个编译为什么会出问题呢

Question

#include <iostream>
using namespace std;
class Rectangle
{
    private:
      int w, h;
      static int totalArea; //矩形总面积
      static int totalNumber; //矩形总数
    public:
        Rectangle(int x,int y):w(x),h(y){ 
        totalArea=w*h; 
        totalNumber++;
      } 
      void display()
      { cout<<"长："<<w<<",高："<<h
      <<",总面积："<<totalArea<<",总数："<<totalNumber<<endl; }
};
int Rectangle::totalArea=w*h;
int Rectangle::totalNumber=0;
int main()
{
    Rectangle r1(2,4),r2(6,8);
    s1.display();
    s2.display();
    return 0;
}

Answer 1

小问题很多呀

#include <iostream>
using namespace std;
class Rectangle
{
    private:
      int w, h;
      static int totalArea; //矩形总面积
      static int totalNumber; //矩形总数
    public:
        Rectangle(int x,int y):w(x),h(y){ 
        totalArea=w*h; 
        totalNumber++;
      } 
      void display()
      { cout<<"长："<<w<<",高："<<h
      <<",总面积："<<totalArea<<",总数："<<totalNumber<<endl; }
};
// 初始化为 0
int Rectangle::totalArea=0;
int Rectangle::totalNumber=0;
int main()
{
    Rectangle r1(2,4),r2(6,8);
    // 要用 r1、r2
    r1.display();
    r2.display();
    return 0;
}