exercise3_3.java

Introduction to java programming 一书中所有编程练习部分的源码

// Exercise3_3: Compute income tax
import javax.swing.JOptionPane;

public class Exercise3_3 {
  /** Main method */
  public static void main(String[] args) {
    // Enter the first edge
    String numberString = JOptionPane.showInputDialog(null,
      "Enter the first edge length (double)",
      "Exercise3_3 Input", JOptionPane.QUESTION_MESSAGE);

    // Convert string to double
    double edge1 = Double.parseDouble(numberString);

    // Enter the second edge
    numberString = JOptionPane.showInputDialog(null,
      "Enter the second edge length (double)",
      "Exercise3_3 Input", JOptionPane.QUESTION_MESSAGE);

    // Convert string to double
    double edge2 = Double.parseDouble(numberString);

    // Enter the third edge
    numberString = JOptionPane.showInputDialog(null,
      "Enter the third edge length (double)",
      "Exercise3_3 Input", JOptionPane.QUESTION_MESSAGE);

    // Convert string to double
    double edge3 = Double.parseDouble(numberString);

    // Display results
    boolean valid = (edge1 + edge2 > edge3) &&
      (edge1 + edge3 > edge2) && (edge2 + edge3 > edge1);

    if (valid) {
      System.out.println("The perimeter of the triangle is " +
        (edge1 + edge2 + edge3));
    }
    else
      System.out.println("Input is invalid");

    System.exit(0);
  }
}