试图理解排序方法.Java家庭作业

Question

这是作业,但我需要"轻推".我找不到如何按名称排序.

我的问题:(请保持答案初学者友好)

1. 到目前为止看起来是否合适？
2. 怎么排序？
3. 有没有人有优化/清洁这个建议？

这是作业:

第6周到期的库存计划第2部分检查点具有以下要求:

1. 修改库存程序,以便应用程序可以处理多个项目.使用数组存储项目.

2. 输出应一次显示一个产品的信息,包括产品编号,产品名称,库存单位数量,每个单位的价格以及该产品的库存价值.

3. 此外,输出应显示整个库存的值.

4. 创建一种方法来计算整个库存的价值.

5. 创建另一种方法,按产品名称对数组项进行排序.

要满足这些要求,您需要将以下内容添加到Inventory类(而不是产品类):

1)声明一个Product类型的数组(一个私有实例变量)

2)在主while循环中,执行以下操作:

a. Instantiate a product object 
b. Populate the product object with the input from the console (like Inventory Part 1     does) 
c. Add the product object reference to the next element in your array 
d. Destroy the reference to the product object variable (note this object was added to your array so you can set the local variable that refers to the object to null)

3)在主while循环之外,执行以下操作:

a. Call a method in your Inventory class to sort the array of Product objects. Note you need to sort an array of Product objects by the Product Name instance variable. To do this, you will need to create a separate .java file that implements the Comparator interface. You will pass the Product array and implemented Comparator interface class as arguments to the sort method of the Arrays class (part of the Java API). 
b. Create a For Loop that iterates through the array of Product objects (similar to the one I have below). Invoke the get method on each instance variable and format the output by calling printf. Sample For Loop to use:
for ( Product product : productArray )  
    {           Add statements here  
    }
c. Call a method in your Inventory class to calculate the total inventory value of all the Product objects in your array. 

这是我的代码

    public class InvTest2{// main method begins
       public static void main( String args[] ) {

        int version = 2;// Version number
        final int invLeng = 5;// Declare Inv length

       // Welcome message
       System.out.printf( "\n%s%d\n" , 
       "Welcome to the Inventory Program v.", version );

       Inv[] DVDs = new Inv[invLeng];
       DVDs[0] = new Inv("The Invisible Man", 0, 8.50); // new DVD constructor
       DVDs[1] = new Inv("The Matrix", 1, 17.99);
       DVDs[2] = new Inv("Se7en", 7, 12.99);
       DVDs[3] = new Inv("Oceans Eleven", 11, 9.99);
       DVDs[4] = new Inv("Hitch Hikers Guide to the Galaxy", 42, 18.69);

        // Display formatted results
        int c = 0;
        double runningValue = 0;
        System.out.printf( "\n%s\n", "Inventory of DVD movies");
        while(c != DVDs.length){
        System.out.printf( "\n\n%s%d\n%s%s\n%s%d\n%s%,.2f\n%s%,.2f\n",
        "Item Number:      ",c,      
        "DVD Title:        ",DVDs[c].getdvdTitle(),
        "Copies in stock:  ",DVDs[c].getdvdInStock(),
        "Price each disk:  $",DVDs[c].getdvdValue(),
        "Value of copies:  $",DVDs[c].getdvdStockValue());//End print
        runningValue += DVDs[c].getdvdStockValue();
        c++;
        }
        System.out.printf( "\n%s%,.2f\n", 
        "Collection Value: $",runningValue);

       }// end method main

}//end class Inventory1

这是库存

public class Inv {//Begin DVD class

   // Declare instance variables
   String dvdTitle;// Declare title as string
   int dvdInStock;// Declare dvdInStock as float
   double dvdValue;// Declare dvdValue as float

   // constructor initializes DVD information
   public Inv(String title, int inStock, double value) { // Initialize (clear) instance variables here
      dvdTitle = title;
      dvdInStock = inStock;
      dvdValue = value;
      } // end constructor

   public String getdvdTitle() {// public method to get the DVD name
      return dvdTitle;}// end method getdvdTitle

   public int getdvdInStock() {// public method to retrieve the dvdInStock
      return dvdInStock;} // end method get dvdInStock

   public double getdvdValue() {// public method to retrieve the dvdValue
      return dvdValue;} // end method get dvdValue

   public double getdvdStockValue() {// public method to dvdStockValue
      return ( dvdValue * dvdInStock );}// end method get dvdStockValue

   } // end class Inv

Answer 1

该任务告诉您要按名称实现排序的具体操作.

休息一下,然后重新阅读"在主循环之外的第一个项目符号点,执行以下操作:".