如何在Java中处理对象中的浮点？

我为这门课写了一个程序，我认为问题是当我测试另一门课的时候

这里是我粘贴的ideone.com的链接

-

-测试仪

 import static java.lang.Math.sqrt;


 public class ThreePoints {

    float x0;
    float y0;
    float x1;
    float y1;
    float x2;
    float y2;


    public ThreePoints(){
        this.x0 = 0;
        this.y0 = 0;
        this.x1 = 0;
        this.y1 = 0;
        this.x2 = 0;
        this.y2 = 0;

    }
    public ThreePoints(float x0, float y0, float x1, float y1, float x2, float y2){
        this.x0 = x0;
        this.y0 = y0;
        this.x1 = x1;
        this.y1 = y1;
        this.x2 = x2;
        this.y2 = y2;
    }
    public double getLength(int side){


     if(side == 0 && isTriangle()){
         return Math.sqrt((x2-x1) * (x2-x1) + (y2-y1) * (y2-y1));
     } else if (side == 1 && isTriangle()){
         return Math.sqrt((x2-x0) * (x2-x0) + (y2-y0) * (y1-y0));
     } else if (side == 2 && isTriangle()){
         return Math.sqrt((x1-x0) * (x1-x0) + (y1-y0) * (y1-y0)); 
     }else{ return 0;

     }
     }
    public double getAngle(int vertex){

            if(vertex == 0 && isTriangle()) {
  double angle = Math.acos((-Math.pow(this.getLength(0),2)
                +Math.pow(this.getLength(1),2)
                +Math.pow(this.getLength(2),2))
                /(2*this.getLength(1)*this.getLength(2)));
                return angle;
           } else if(vertex == 1 && isTriangle()) {
  double angle = Math.acos((Math.pow(this.getLength(0),2)- Math.pow(this.getLength(1),2)
                +Math.pow(this.getLength(2),2))/
                (2*this.getLength(0)*this.getLength(2)));
                return angle;
           } else if(vertex == 2 && isTriangle()){
  double angle = Math.acos((Math.pow(this.getLength(0),2)
                 +Math.pow(this.getLength(1),2)- Math.pow(this.getLength(2),2)) /(2*this.getLength(0)*this.getLength(1)));
                 return angle;
           } else {
                 return 0;
                   }


           }
    public boolean isTriangle(){

 if (!(x0 * (y1-y2) + x1 * (y2-y0) + x2 * (y0-y1) == 0)){
     return true;
 } 
     return false;
    }
    public boolean isEquilateral(){
          if (getLength(0) != getLength(1))
              return false;
          if (getLength(0) != getLength(2))
              return false;
          if (getLength(1) != getLength(2))
              return false;
          return true;
    }
    public boolean isIsosceles(){
        if (getLength(0) == getLength(1))
            return true;
        if (getLength(0) == getLength(2))
            return true;
        if (getLength(1) == getLength(2))
            return true;
        return false;

    }
    public boolean isScalene(){
        if (getLength(0) == getLength(1))
            return true;
        if (getLength(0) == getLength(2))
            return true;
        if (getLength(1) == getLength(2))
            return true;
        return false;
    }
    public boolean isAcute(){
        if (getAngle(0) < 90 && getAngle(1) < 90 && getAngle(2) < 90){
            return true;
        }
        return false;
    }
    public boolean isObtuse(){
        if (getAngle(0) > 90 && getAngle(1) > 90 && getAngle(2) > 90){
            return true;
        }      
        return false;
    }
    public double getPerimeter(){
        double perimeter;
        perimeter = (getLength(0) + getLength(1) + getLength(2));
        return perimeter;
    }
    public boolean isRight(){
    if (getAngle(0) == 90 && getAngle(1) == 90 && getAngle(2) == 90){
    return true;
    }
    return false;
    }
    public double getArea(){
    double s = ((getLength(0) + getLength(1) + getLength(2))/2);    
    double area = sqrt(s * (s-getLength(0))*(s-getLength(1))*(s-getLength(2)));

        return area;
    }
    private boolean approxEqual (double x, double y) {
        return Math.abs(x - y) <= 1E-12;
    }
    }

----------------------------------------------*

  ThreePoints tp2 = new ThreePoints(3.32, 2.32, 2.12, 4.54, 5.43, 4.23);

  double tpAngle0 = tp2.getAngle(0);
  double tpAngle1 = tp2.getAngle(1);
  double tpAngle2 = tp2.getAngle(2);

  System.out.println("tp2 angle 0 is " + tpAngle0);
  System.out.println("tp2 angle 1 is " + tpAngle1);
  System.out.println("tp2 angle 2 is " + tpAngle2);

    double tpLength0 = tp2.getLength(0); 
   double tpLength1 = tp2.getLength(1); 
   double tpLength2 = tp2.getLength(2);

  System.out.println("tp2 side 0 is " + tpLength0);
  System.out.println("tp2 side 1 is " + tpLength1);
  System.out.println("tp2 side 2 is " + tpLength2);

tp2.isTriangle();
tp2.isEquilateral();
tp2.isIsosceles();
tp2.isScalene();
tp2.isAcute();
tp2.isObtuse();
tp2.isRight();






 }

 }

看--------------------------

当我试图创建那个对象时，Java给了我一个错误。我对Java还是相当陌生的，所以我只是想了解我做错了什么。而且我的布尔方法似乎不打印真或假

试试这个

新的三个点（3.32f、2.32f、2.12f、4.54f、5.43f、4.23f）

默认情况下，这样的数字文本是双倍的。
您需要添加一个

f

，使它们显式浮动

不确定您是如何测试布尔方法的

---

如果您的代码未编译

看起来您在这里复制变量（

tpAngleX

和

tpLengthX

）：

如果要在同一方法中重复使用变量，只需声明一次：

double tpAngle0 = tp.getAngle(0);

...

tpAngle0 = tp.getAngle(0);

---

你得到了什么错误？方法不会打印任何东西，除非它们有一个打印东西的语句。这些方法返回

true

或

false

，但您只是在抛出结果。尝试

System.out.println（“isTriangle=“+tp.isTriangle（））

或类似的方法。“给我一个错误”不是错误描述。Java生成了一些非常好的错误消息。在此处复制消息（编辑您的原始帖子并粘贴），并指出消息标识的行。太棒了，谢谢！我几乎没用过浮子。现在我知道了！

double tpAngle0 = tp.getAngle(0);
double tpAngle1 = tp.getAngle(1);
double tpAngle2 = tp.getAngle(2);

...

double tpAngle0 = tp.getAngle(0);
double tpAngle1 = tp.getAngle(1);
double tpAngle2 = tp.getAngle(2);

double tpAngle0 = tp.getAngle(0);

...

tpAngle0 = tp.getAngle(0);