while循环在输入值之前首先打印双精度

Question

在询问切换器的输入之前，字符串 asd 打印双倍，我现在感到绝望。我希望字符串“asd”只打印一次，但在我的情况下打印两次，我的猜测是错误或循环，抱歉，我是这里的新手，对编程很陌生

public class FruitBasket {

static String option;

static String choice1;

static int catcher;

static int counter1 = 1;

static int counter = 0;

static String eater = "e";

static Scanner sc = new Scanner(System.in);       

static Stack<String> basket = new Stack();

static String switcher;

public static void main(String[] args) {

    catching();

}

static void catching(){

    System.out.println("Catch and eat any of these fruits: " + "'apple', 'orange', 'mango', 'guava'" );

    System.out.println("A apple, O orange, M mango, G guava");

    System.out.print("How many fruits would you like to catch? ");

    catcher = sc.nextInt();

    switches();

     }

     static void switches(){

    while(counter1 < catcher)  {

    String asd = "Fruit " + counter1 + " of " + catcher + ":";

    System.out.print(asd);

    switcher = sc.nextLine();

         switch (switcher) {

            case "a":

                basket.push("apple");

                counter++;

                counter1++;

                break;

Answer 1

这是因为您使用 sc.nextInt() 来获取用户的输入，并且它不会消耗该行，因此当您使用 switcher = sc.nextLine(); 时&nbsp;它仍然读取用户之前输入的号码。您可以在 catcher = sc.nextInt(); 之后添加此内容&nbsp;消耗该行：&nbsp;&nbsp;&nbsp;&nbsp;if&nbsp;(sc.hasNextLine()){ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sc.nextLine(); &nbsp;&nbsp;&nbsp;&nbsp;}或者您也可以使用：catcher&nbsp;=&nbsp;Integer.parseInt(sc.nextLine());将用户输入转换为整数值也将起作用。