totalarea.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。

// TotalArea.java: Test passing an array of objects to the method
public class TotalArea
{
  // Main method
  public static void main(String[] args)
  {
    // Declare circleArray
    Circle[] circleArray;

    // Create circleArray
    circleArray = createCircleArray();

    // Print circleArray and total areas of the circles
    printCircleArray(circleArray);
  }

  // Create an array of Circle objects
  public static Circle[] createCircleArray()
  {
    Circle[] circleArray = new Circle[10];

    for (int i=0; i<circleArray.length; i++)
    {
      circleArray[i] = new Circle(Math.random()*100);
    }

    // Return Circle array
    return circleArray;
  }

  public static void printCircleArray(Circle[] circleArray)
  {
    System.out.println("The radii of the circles are");
    for (int i=0; i<circleArray.length; i++)
    {
      System.out.print("\t\t\t\t" +
        circleArray[i].getRadius() + '\n');
    }

    System.out.println("\t\t\t\t-------------------");

    // Compute and display the result
    System.out.println("The total areas of circles is \t" +
      sum(circleArray));
  }

  // Add circle areas
  public static double sum(Circle[] circleArray)
  {
    // Initialize sum
    double sum = 0;

    // Add areas to sum
    for (int i = 0; i < circleArray.length; i++)
      sum += circleArray[i].findArea();

    return sum;
  }
}