testcirclewithconstructors.java

此源码为机械工业出版社出版的《Java语言程序设计》第三版所配套的书中所有源代码。

// TestCircleWithConstructors.java: Demonstrate constructors
public class TestCircleWithConstructors
{
  // Main method
  public static void main(String[] args)
  {
    // Create a Circle with radius 5.0
    Circle myCircle = new Circle(5.0);
    System.out.println("The area of the circle of radius "
      + myCircle.radius + " is " + myCircle.findArea());

    // Create a Circle with default radius
    Circle yourCircle = new Circle();
    System.out.println("The area of the circle of radius "
      + yourCircle.radius + " is " + yourCircle.findArea());
  }
}

/*
// Circle with two constructors
class Circle
{
  double radius;

  // Default constructor
  Circle()
  {
    radius = 1.0;
  }

  // Construct a circle with a specified radius
  Circle(double r)
  {
    radius = r;
  }

  // Find area of this circle
  double findArea()
  {
    return radius*radius*3.14159;
  }
} */