java - 当我输入一个整数时，为什么我的 Java 双变量类型会变成 0.0？

Question

我正在使用驱动程序类来创建另一个类的对象。当我输入宠物体重或整数时，数字为 0.0。所有权重变量都声明为 double ，所以我不知道为什么要这样做。

  import java.util.Scanner;

    public class PetAssignment {

        public static void main(String[] args) 
        {
            String nameAndType;
            int yrs;
            double lbs;

            //Scanner object for the keyboard input
            Scanner answers = new Scanner(System.in);

            //Pet objects used for calling accessor methods
            Pet petName = new Pet();
            Pet petType = new Pet();
            Pet petAge = new Pet();
            Pet petWeight = new Pet();

            //A bunch of other code and pet attributes

            //Input for the weight of pet
            System.out.print("How many pounds does your pet weight? ");
            lbs = answers.nextDouble();
            petName.setWeight(lbs);

            //Print out of the user's answers
            System.out.println(""); 
            System.out.println("You have a "+ petType.getType() + ". That is named " 
                + petName.getName()+ " and is " 
                + petAge.getAge() + " years old and weighs " 
                + petWeight.getWeight() + " lbs.");         
        }
    }

这是我的宠物类(class)

 public class Pet 
    {
      private String name;
      private String type;
      private int age;
      private double weight;    
      /*
       * a bunch of other code
       */
      public void setWeight(double petWeight)
      {
          weight = petWeight;
      }
      /*
       * a bunch of other code
       */
      public double getWeight()
      {
          return weight;
      }
    }

Answer 1

错误的是您使用此代码来设置值

 petName.setWeight(lbs);

并用它来检索值

 Pet petWeight = new Pet();

它们是2个不同的对象，您必须在设置、检索中为2个语句使用相同的对象通过放置

petWeight.setWeight(lbs);

而不是

petName.setWeight(lbs);

解决了