wr01.cpp

teach yourself C++ in 21 days 第五版

/* Listing: WR01.cpp
 * Description: Week in Review listing for week 1
 *===============================================*/
#include <iostream>
using namespace std;

enum CHOICE { 
      DrawRect = 1, 
      GetArea, 
      GetPerim, 
      ChangeDimensions, 
      Quit  };

// Rectangle class declaration
class Rectangle
{
  public:
     // constructors
     Rectangle(int width, int height);
     ~Rectangle();

     // accessors
     int GetHeight() const { return itsHeight; }
     int GetWidth() const { return itsWidth; }
     int GetArea() const { return itsHeight * itsWidth; }
     int GetPerim() const { return 2*itsHeight + 2*itsWidth; }
     void SetSize(int newWidth, int newHeight);

     // Misc. methods

  private:
     int itsWidth;
     int itsHeight;
};

// Class method implementations
void Rectangle::SetSize(int newWidth, int newHeight)
{
   itsWidth = newWidth;
   itsHeight = newHeight;
}

Rectangle::Rectangle(int width, int height)
{
   itsWidth = width;
   itsHeight = height;
}

Rectangle::~Rectangle() {}

int DoMenu();
void DoDrawRect(Rectangle);
void DoGetArea(Rectangle);
void DoGetPerim(Rectangle);

/*===============================================*/
int main()
{
   // initialize a rectangle to 30,5
   Rectangle theRect(30,5);

   int choice = DrawRect;
   int fQuit = false;

   while (!fQuit)
   {
     choice = DoMenu();
     if (choice < DrawRect || choice >  Quit)
     {
        cout << "\nInvalid Choice, try again. ";
        cout << endl << endl;
        continue;
     }
     switch (choice)
     {
       case  DrawRect:
          DoDrawRect(theRect);
          break;
       case GetArea:
          DoGetArea(theRect);
          break;
       case GetPerim:
          DoGetPerim(theRect);
          break;
       case ChangeDimensions:
          int newLength, newWidth;
          cout << "\nNew width: ";
          cin >> newWidth;
          cout << "New height: ";
          cin >> newLength;
          theRect.SetSize(newWidth, newLength);
          DoDrawRect(theRect);
          break;
       case Quit:
          fQuit = true;
          cout << "\nExiting... " << endl << endl;
          break;
       default:
          cout << "Error in choice!" << endl;
          fQuit = true;
          break;
     }   // end switch
   }     // end while
   return 0;
}       // end main

int DoMenu()
{
   int choice;
   cout << endl << endl;   // create two new lines
   cout << "   *** Menu *** "   << endl;
   cout << "(1) Draw Rectangle" << endl;
   cout << "(2) Area"           << endl;
   cout << "(3) Perimeter"      << endl;
   cout << "(4) Resize"         << endl;
   cout << "(5) Quit"           << endl;

  cin >> choice;
  return choice;
}

 void DoDrawRect(Rectangle theRect)
 {
   int height = theRect.GetHeight();
   int width = theRect.GetWidth();

   for (int i = 0; i<height; i++)
   {
     for (int j = 0; j< width; j++)
        cout << "*";
     cout << endl;
   }
 }


 void DoGetArea(Rectangle theRect)
 {
   cout << "Area: " <<  theRect.GetArea() << endl;
 }

 void DoGetPerim(Rectangle theRect)
 {
   cout << "Perimeter: " <<  theRect.GetPerim() << endl;
 }
// ==========   End of Listing   ==========