Java错误：无法找到符号

Question

我一直在这个程序的工作一段时间了，我一直在努力。我是编程新手，所以我不知道如何解决它。到目前为止，我已经设法摆脱了大部分错误，但这是我出于某种原因无法修复的错误。有人能帮我吗？我真的很感激。

import java.util.Scanner; 
import java.util.ArrayList; 
public class PetSorter 
{ 
    public static void main (String [] args) 
    { 
    ArrayList<Pet> strList = new ArrayList<Pet>(); 
    Boolean another = true; 
    Scanner keyboard = new Scanner(System.in); 
    while(another) 
    { 
     System.out.println("Enter the pet's name: "); 
     String nam = keyboard.nextLine(); 
     Pet p = new Pet(nam); //here is where the Error occurs 
     strList.add(p); 

     System.out.println("Would you like to enter another pet's name? (y/n)"); 
     String answer = keyboard.nextLine(); 
     another = answer.equalsIgnoreCase("y"); 
    } 

    PetSorter.nameSort(strList); 
    for (int x = 0; x < strList.size(); x++) 
    { 
     System.out.println(strList.get(x).getName()); 
    } 
    } 

    public static void nameSort (ArrayList<Pet> array) 
    { 
    for (int i = 1; i < array.size(); i++) 
    { 
     int j = i; 
     Pet tp = array.get(i); 
     String B = array.get(i).getName(); 
     while ((j > 0) && (array.get(j-1).getName().compareTo(B) > 0)) 
     { 
     array.set(j, array.get(j-1)); 
     j--; 
     } 
     array.set(j,tp); 
    } 
    } 
} 

这里是低于

import java.util.ArrayList; 
import java.util.Scanner; 
public class Pet 
{ 
    private String name; 
    private int age; //in years 
    private double weight; //in pounds 

    /** 
    This main is just a demonstration program. 
    */ 
    public static void main(String[] args) 
    { 
     Pet myDog = new Pet(); 
     myDog.set("Fido", 2, 5.5); 
     myDog.writeOutput(); 
     System.out.println("Changing name."); 
     myDog.set("Rex"); 
     myDog.writeOutput(); 
     System.out.println("Changing weight."); 
     myDog.set(6.5); 
     myDog.writeOutput(); 
     System.out.println("Changing age."); 
     myDog.set(3); 
     myDog.writeOutput(); 
    } 

    public void writeOutput() 
    { 
     System.out.println("Name: " + name); 
     System.out.println("Age: " + age + " years"); 
     System.out.println("Weight: " + weight + " pounds"); 
    } 

    public void set(String newName) 
    { 
     name = newName; 
     //age and weight are unchanged. 
    } 

    public void set(int newAge) 
    { 
     if (newAge <= 0) 
     { 
      System.out.println("Error: illegal age."); 
      System.exit(0); 
     } 
     else 
      age = newAge; 
     //name and weight are unchanged. 
    } 

    public void set(double newWeight) 
    { 
     if (newWeight <= 0) 
     { 
      System.out.println("Error: illegal weight."); 
      System.exit(0); 
     } 
     else 
      weight = newWeight; 
     //name and age are unchanged. 
    } 

    public void set(String newName, int newAge, double newWeight) 
    { 
     name = newName; 
     if ((newAge <= 0) || (newWeight <= 0)) 
     { 
      System.out.println("Error: illegal age or weight."); 
      System.exit(0); 
     } 
     else 
     { 
      age = newAge; 
      weight = newWeight; 
     } 
    } 

    public String getName() 
    { 
     return name; 
    } 


    public int getAge() 
    { 
     return age; 
    } 
    public double getWeight() 
    { 
     return weight; 
    } 
} 

Answer 1

宠物类添加到您的Pet类所需constrcutor：

public class Pet { 

    String name; 

    ... 

    public Pet (String name) { 
     this.name = name; 
    } 

    ... 

} 

Answer 2

更换

Pet p = new PetSorter().new Pet(nam); //here is where the Error occurs 

，并添加类宠物

新代码：

import java.util.Scanner; 
import java.util.ArrayList; 
public class PetSorter 
{ 

public class Pet 
{ 
    String name; 

    public Pet(String _name) 
    { 
    name=_name; 
    } 

    public String getName() 
    { 
    return name; 
    } 
} 


    public static void main (String [] args) 
    { 
    ArrayList<Pet> strList = new ArrayList<Pet>(); 
    Boolean another = true; 
    Scanner keyboard = new Scanner(System.in); 
    while(another) 
    { 
    System.out.println("Enter the pet's name: "); 
    String nam = keyboard.nextLine(); 

    Pet p = new PetSorter().new Pet(nam); //here is where the Error occurs 
    strList.add(p); 

    System.out.println("Would you like to enter another pet's name? (y/n)"); 
    String answer = keyboard.nextLine(); 
    another = answer.equalsIgnoreCase("y"); 
    } 

    PetSorter.nameSort(strList); 
    for (int x = 0; x < strList.size(); x++) 
    { 
    System.out.println(strList.get(x).getName()); 
    } 
    } 

    public static void nameSort (ArrayList<Pet> array) 
    { 
    for (int i = 1; i < array.size(); i++) 
    { 
    int j = i; 
    Pet tp = array.get(i); 
    String B = array.get(i).getName(); 
     while ((j > 0) && (array.get(j-1).getName().compareTo(B) > 0)) 
     { 
    array.set(j, array.get(j-1)); 
    j--; 
     } 
    array.set(j,tp); 
    } 
    } 
} 

Answer 3

Pet p = new Pet(nam);，Pet类没有一个构造函数的参数。