Question

所以我有一个库存程序，其中的符号存储在数组中，我需要将该数组调用到另一个类中并打印出来。这是我的代码和数组代码。

abstract class stockArray
{

   String stocks[];

   String stockSymbols[] ={ "SMG", "APL", "GE", "TOY","SUB","GM","LG","VZ","JP","BTN"};

}

这是我需要调用并打印出我的Switch case语句的第1种情况的代码。我如何将该数组调用到该位置（情况1）并打印该数组的内容？谢谢

 public class stockProgram  
 {

    public static void main(String[] args) 
     {

       String s;

      Scanner sc= new Scanner(System.in);
      Scanner input = new Scanner(System.in);
      Scanner dec = new Scanner(System.in);       

    System.out.println("Welcome to the stock tracker Program,");

    System.out.println("What would you like to do?");

    System.out.println("***MENU OPTIONS***");

    System.out.println("1. See a list of stocks");
    System.out.println("2. Buy stocks");
    System.out.println("3. Sell Stock Holdings.");
    System.out.println("4. Search Stock listings");
    System.out.println("5. Exit Program");

    System.out.println(" Please Enter an option");        

    int op = sc.nextInt();
        switch(op)
    {


      case 1: System.out.println("---Stock Holdings List---");
              System.out.println("These are the current stocks avaliable to purchase in this program.");

     break;

Answer 1

首先，请遵循命名约定-类名以大写字母开头，因此将stockArray更改为StockArray。

访问该数组的一种方法是像这样使它static：-

static final String stockSymbols[] ={ "SMG", "APL", "GE", "TOY","SUB","GM","LG","VZ","JP","BTN"};

，然后在您的case语句中使用此代码：-

String symbols[] = StockArray.stockSymbols;
Arrays.stream(symbols).forEach(System.out::println);

或者，如果您不想使其成为静态，则可以创建一个匿名内部类：-

String symbols[] = new StockArray() {}.stockSymbols;
Arrays.stream(symbols).forEach(System.out::println);

请注意，我只是将该数组存储在另一个变量symbols中，仅用于演示目的，您不需要这样做。

Answer 2

定义一个扩展抽象类stockArray的类：

class StockArraySubclass extends stockArray {
}

在StockArraySubclass类的切换情况下使用stockProgram：

StockArraySubclass st = new StockArraySubclass();
System.out.println(Arrays.toString(st.stockSymbols));

这将打印：[SMG, APL, GE, TOY, SUB, GM, LG, VZ, JP, BTN]

Answer 3

首先您的stockArray类是抽象的（更好的类名称以大写字母开头，即StockArray），并且您知道抽象类不能是实例。因此，您必须做出决定，再创建另一个类，该类扩展您的抽象类（stockArray）或使您的抽象类成为普通类。那么您可以创建一个实例

，您只需在主要方法中使用

public class stockArray
   {

       String stocks[];

       String stockSymbols[] ={ "SMG", "APL", "GE","TOY","SUB","GM","LG","VZ","JP","BTN"};

       }


 public class stockProgram

{

public static void main(String[] args) 
 {

   String s;

  Scanner sc= new Scanner(System.in);
  Scanner input = new Scanner(System.in);
  Scanner dec = new Scanner(System.in);   
stockArray stockArr = new stockArray();    

System.out.println("Welcome to the stock tracker Program,");

System.out.println("What would you like to do?");

System.out.println("***MENU OPTIONS***");

System.out.println("1. See a list of stocks");
System.out.println("2. Buy stocks");
System.out.println("3. Sell Stock Holdings.");
System.out.println("4. Search Stock listings");
System.out.println("5. Exit Program");

System.out.println(" Please Enter an option");        

int op = sc.nextInt();
    switch(op)
{


  case 1: 
          forEach(String str : stockArr.stockSymbols){
          System.out.println(str);
    }
          System.out.println("These are the current stocks avaliable to purchase in this program.");

 break;

需要调用一个数组并在另一个类中打印它

3 个答案: