while 循环在输入值之前先进行双重打印[关闭]

Question

String asd 在请求切换器的输入之前打印 double，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，对不起，我在这里很新并开始编程

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消耗线路所以当您使用 switcher = sc.nextLine();它仍然会读取用户之前输入的数字。

你可以在 catcher = sc.nextInt(); 之后添加这个消费线：

    if (sc.hasNextLine()){
        sc.nextLine();
    }

或者你也可以使用：

catcher = Integer.parseInt(sc.nextLine());

将用户输入转换为整数值，它也可以工作。