list1002.cpp

teach yourself C++ in 21 days 第五版

//Listing 10.2 Default values in member functions
 
#include <iostream>
 
using namespace std;
 
// Rectangle class declaration
class Rectangle
{
   public:
     // constructors
     Rectangle(int width, int height);
     ~Rectangle(){}
     void DrawShape(int aWidth, int aHeight, 
          bool UseCurrentVals = false) const;
 
   private:
     int itsWidth;
     int itsHeight;
};
 
//Constructor implementation
Rectangle::Rectangle(int width, int height):
itsWidth(width),       // initializations
itsHeight(height)
{}                     // empty body
 
 
// default values used for third parameter
void Rectangle::DrawShape(
int width,
int height,
bool UseCurrentValue
) const
{
    int printWidth;
    int printHeight;
 
    if (UseCurrentValue == true)
    {
       printWidth = itsWidth;       // use current class values
       printHeight = itsHeight;
    }
    else
    {
       printWidth = width;         // use parameter values
       printHeight = height;
    }
 
 
    for (int i = 0; i<printHeight; i++)
    {
       for (int j = 0; j< printWidth; j++)
       {
          cout << "*";
       }
       cout << endl;
    }
 }
 
// Driver program to demonstrate overloaded functions
int main()
{
    // initialize a rectangle to 30,5
    Rectangle theRect(30,5);
    cout << "DrawShape(0,0,true)..." << endl;
    theRect.DrawShape(0,0,true);
    cout <<"DrawShape(40,2)..." << endl;
    theRect.DrawShape(40,2);
    return 0;
}