Question

我似乎无法弄清楚为什么我的addRecord（）方法正在循环。具体而言，它仅在“输入销售ID＆gt;＆gt;”处循环在方法的第一个if / else中。我试过在代码末尾调用programMenu（）方法，但编译器只是继续尝试运行它们。此方法应仅在switch case语句中接收到“a”时执行，但在输入“a”和“c”时运行，然后在“Enter Sales ID＆gt;＆gt;”处继续循环到相同的else语句。 ”。

我的方法如下：

putArrayToDb = (tableName, arrayToPut) => {
    if (this.dbPromise) {
        this.dbPromise.then(db => {
            if (!db) return;

            var tx = db.transaction(tableName, 'readwrite');
            var store = tx.objectStore(tableName);
            arrayToPut.map(arrayItem => {
                store.put(arrayItem);
            });
        })
    }
}

putArrayToDb('categories', ["value1", "value2", "value3"]);

我的开关案例如下：

public static int addRecord(Salesperson[]salesPeopleArray, int 
numOfSalesPpl)
    {
        String name=null;
        String idNum;  
        double salesAmt = 0;
        String response;
        numOfSalesPpl = 0;
        final int MAX_LIMIT=20;
        final int ID_NUM_LIMIT = 8; 

        if(numOfSalesPpl == MAX_LIMIT)
        {
            System.out.print("Database has reached capacity.");
            System.out.print(" Please delete a record before ");
            System.out.println("adding to the database.");
        }
        else
        System.out.print("Enter Sales ID:>> ");
        idNum = userInput.nextLine();

        if(idNum.length() != ID_NUM_LIMIT)
        {
           System.out.println(">>>>>Sales ID must be 8 digits<<<<<<"); 
           programMenu();
        }
        else
        {
           System.out.print("Please enter name: >> ");
           name = userInput.nextLine();
           System.out.print("Sales amount : >> ");
           salesAmt = userInput.nextDouble();
           salesPeopleArray[numOfSalesPpl] = new Salesperson(name, 
idNum,salesAmt);    
           ++numOfSalesPpl; 
           userInput.nextLine();
           System.out.print("Do you want to display database> Y/N >>");
           response = userInput.nextLine();
           if(response.equals("y"))     

           displayDatabase(salesPeopleArray, numOfSalesPpl);
    }

    return numOfSalesPpl;
    }

我的programMenu（）方法如下所示：

String selection = programMenu();
   boolean loop = true;


     do
       {
          switch(selection)
          {
               case "A": 
               case "a":                     
                  addRecord(salesPeopleArray, numOfSalesPpl);
                  break;

                case "C": 
                case "c": 
                   changeRecord(numOfSalesPpl, salesPeopleArray);
                   break;

                case "Q": 
                case "q":
                System.out.print("You Are Leaving Database");
                System.out.print("   ");
                loop = false;
                break;
           }
       }
     while(loop); 

}

Answer 1

这里你的代码只有一次获得用户输入（“A / a”）然后进入循环因为“selection”in已经值“A”所以。当你将此行“ String selection = programMenu（）; ”放在循环内，循环时间询问用户输入，您可以更改switch case语句。

  boolean loop = true;
     do
       {
          String selection = programMenu();
          switch(selection)
          {
               case "A": 
               case "a":                     
                  addRecord(salesPeopleArray, numOfSalesPpl);
                  break;

                case "C": 
                case "c": 
                   changeRecord(numOfSalesPpl, salesPeopleArray);
                   break;

                case "Q": 
                case "q":
                System.out.print("You Are Leaving Database");
                System.out.print("   ");
                loop = false;
                break;
           }
       }
     while(loop);     
}

为什么我的方法循环没有循环？

1 个答案: