小编Jus*_*pee的帖子

class Shape 
{
   public:
      virtual void draw() const {cout<<"draw shape"<<endl;}
};



class Point : public Shape 
{
   public:
      Point( int a= 0, int b = 0 ) {x=a; y=b;}  // default constructor
      int getx() const {return x;}
      int gety() const {return y;}
      virtual void draw() const {cout<<"draw point("<<x<<","<<y<<")\n";}
   private:
      int x, y;   // x and y coordinates of Point
};


class Circle : public Point 
{
   public:  // default constructor
      Circle( double r = 0.0, int x = 0, int …

#include <iostream>
#include <string>

using namespace std;
int main()
{
    char option='0';
    do
    {

        cin >> option;
        switch (option) 
        {
            case '1':
                cout << "testing 1\n";
                break;
            case '2':
                cout << "testing 2\n";
                break;
            case '3':
                cout << "Thank you, Have a nice day.\n";
                break;

            default:
                cout << "Invalid option, Please enter option (1-3).";
        }

    }while (option != 3);

    return 0;
}

我不知道为什么while循环是无限的.当我键入时3,它应该打印出来Thank you, Have a nice day.并退出循环while (option != 3).但是,似乎while循环不起作用.