java - 在 toString() 中设置属性/实例变量和打印

Question

我必须返回三角形的面积和周长。我在主文件中制作了 2 个函数。 这是我的 toString() 函数:

public String toString()
   {
      String printPerimeter = "The perimiter is " + perimeter;
      String printArea = "The area is " + area;
      return printPerimeter;
      return printArea;
   }

然后我将该代码上方的周长和面积设置为:

private double area;
private double perimeter;

我的二传手函数:

public double setPerimiter()
   {
      perimeter = (sideA + sideB + sideC);
      return perimeter;
   }

   public double setArea()
   {
      double s = (sideA+sideB+sideC)/2.0;
      area = Math.sqrt(s*((s-sideA)*(s-sideB)*(s-sideC)));
      return area;
   }

我确定我返回的方式有问题。但它一直在说 Triangle.java:52: error: unreachable statement

  return printPerimeter;
  return printArea;

有什么帮助吗？

Answer 1

一个函数只能返回一个语句。

public String toString()
  {
  String printPerimeter = "The perimiter is " + perimeter;
  String printArea = "The area is " + area;

  return printPerimeter; <-- This will be returned

  return printArea; <-- Program control will never reach here 
and hence you are getting the error "unreachable code"

 }

类似于两个setter，需要有两个getter:

public String getPermiter()
{
  String printPerimeter = "The perimiter is " + perimeter;
  return printPerimeter;
  }


public String getArea()
{
  String printArea = "The area is " + area;
  return printArea;
}