java - 我正在尝试编写代码以计算周长，但结果是0.0单位

我的支持班

/*
 *Calculates Perimeter of three triangles
 */

public class Triangle{
  //data field declarations
  public int x1;        // coordinates of first point of the triangle
  public int y1;
  public int x2;       // coordinates of second point of the triangle
  public int y2;
  public int x3;      // coordinates of third point of the triangle
  public int y3;
  private double side1, side2, side3, perimeter;
  private String m;

  public Triangle(String m, int x1, int y1, int x2, int y2, int x3, int y3)
  {
    this.m = m;
    this.x1 = x1;
    this.y1 = y1;
    this.x2 = x2;
    this.y2 = y2;
    this.x3 = x3;
    this.y3 = y3;
  }

  public void calculateSideLength()
  {
    side1 = Math.sqrt(Math.pow((x2-x1),2)*Math.pow((y2-y1),2));
    side2 = Math.sqrt(Math.pow((x3-x2),2)*Math.pow((y3-y2),2));
    side3 = Math.sqrt(Math.pow((x3-x1),2)*Math.pow((y3-y1),2));
  }

  public void calculateTrianglePerimeter()
  {
    perimeter = side1+side2+side3;
  }

   public String toString()
  {
    return "Triangle " + m +  " perimeter is " + perimeter + " units";
   }
 }

我的申请班

/*
 *Calculates Perimeter of three triangles
 */

public class TriangleApp{
  public static void main (String[] args){
    Triangle a = new Triangle("A", 0,3,3,4,1,9);
    System.out.println(a.toString());
  }
}

我得到三角形的周长是0.0单位
有人可以告诉我我在做什么错吗？

最佳答案

您不是在呼叫calculateSideLength()或calculateTrianglePerimeter()。调用它们（从构造函数，该顺序或从用户代码），然后将设置值。

关于java - 我正在尝试编写代码以计算周长，但结果是0.0单位，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/7426446/