Question

我想提示用户三角形的三边。然后弄清楚三角形是直角三角形，等边形还是等腰形。但我的程序只是在错误处理中遇到错误并在尝试获取side(1)时退出程序。所以我的问题是你看到我的代码导致了什么或出了什么问题？

驱动程序TestTriangle.java

public class TestTriangle { 
  public static void main(String[] args) {
    System.out.println("Welcome to the Triangle Program");
    System.out.println();

    Triangle myTriangle = new Triangle();
    myTriangle.buildTriangle();

    System.out.println();
    System.out.println("My analysis of this triangle is");
    System.out.println();

    myTriangle.classifyTriangle();

    String prettyPerim = String.format("%.3g", myTriangle.perimeter());
    String prettyArea = String.format("%.3g", myTriangle.area());

    System.out.println("\tThe area of the triangle is " + prettyArea + ".");
    System.out.println("\tThe perimeter of the triangle is " + prettyPerim + ".");
   }
}

程序Triangle.java

import java.util.Scanner;
import java.util.InputMismatchException;

public class Triangle {
  public static final double TOLERANCE = 0.0001;

  private double min;
  private double mid;
  private double max;  
  private Scanner input;

  public Triangle() {
    double side1 = 0.0, side2 = 0.0, side3 = 0.0;
  }

  public void buildTriangle() {
    double side1 = getSide(1);
    double side2 = getSide(2);
    double side3 = getSide(3);

    // if side1 is greater than side2, the min is side1 and the max is side2
    if (side1 < side2) {
      min = side1;
      max = side2;
    // otherwise the min is side2 and the max is side1
    } else {
      min = side2;
      max = side1;
    }

    // if side3 is less than the min value, then the mid value is the min value and the min value is side3
    if (side3 < min) {
      mid = min;
      min = side3;
    // if side3 is greater than the max value then the mid is the max and the max is side3
    } else if (side3 > max) {
      mid = max;
      max = side3;
    // otherwise the mid is side3
    } else {
      mid = side3;
    }
  }

  public double getSide(int index) {
    System.out.print("Please enter the length of side " + index + ": ");
    double sideVal = 0.0;
    try{
      sideVal = input.nextDouble();
    } catch (Exception e) {
      System.out.println("You did not enter a valid input. Exiting.");
      System.exit(1);
    }
    return sideVal;
  }

  public void classifyTriangle() {
    // if the max value is greater than the min and the mid combined it is not a triangle, exit the program.
    if (max > min + mid) {
      System.out.println("Not a triangle");
      System.exit(1);
    }
    else if (((Math.pow(min, 2)) + (Math.pow(mid, 2))) == (Math.pow(max, 2))) {      
      System.out.println("This is a right triangle");
    }
    else if (max == min || min == mid || max == mid) {
      if (max == min && min == mid && max == mid) {      
        System.out.println("This is an equilateral triangle");
      }
      else {
        System.out.println("This is an isosceles triangle");
      }
    }
  }

  public double perimeter() {
    // calculate the perimeter
    double perimeter = max + mid + min;
    return perimeter;
  }

  public double area() {
    // calculate the area
    double semi = (max + mid + min) / 2;
    double product = (semi - max) * (semi - mid) * (semi - min) * semi;
    double area = Math.sqrt(product);
    return area;
  }
}

Answer 1

您需要初始化您的输入

    input = new Scanner(System.in);

Java中的三角分析

1 个答案: