java - 需要帮助修改输入验证和错误消息的代码

Question

我的代码需要一些帮助。我正在尝试修改书面代码以询问用户"is"或“否”以便循环继续。如果用户输入"is"或“否”以外的任何内容，我应该使用主要读取和 while 循环来显示错误消息。

public static void main(String[] args) {
  Scanner input = new Scanner(System.in);
  //declare local variables
  String endProgram = "no";
  boolean inputValid;

  while (endProgram.equals("no")) {
    resetVariables();
    number = getNumber();
    totalScores = getScores(totalScores, number, score, counter);
    averageScores = getAverage(totalScores, number, averageScores);
    printAverage(averageScores);
    do {
      System.out.println("Do you want to end the program? Please enter yes or no: ");
     input.next();
     if (input.hasNext("yes") || input.hasNext("no")) {
       endProgram = input.next();
     } else {
       System.out.println("That is an invalid input!");
     }
  }
  while (!(input.hasNext("yes")) || !(input.hasNext("no")));
 }
}

Answer 1

hasNext 方法调用不带任何参数。看看docs .

因此您应该首先获取输入的值:

String response = input.next();

然后测试响应:

!response.equalsIgnoreCase('yes') || !response.equalsIgnoreCase('no')

您可以将此测试放入一个方法中，因为您多次检查同一事物。

将 endProgram 更改为 boolean 值可能会更容易查看程序的逻辑。甚至可能将其重命名为 running;

boolean running = true;
...
while (running) {
  ...
  String response;
  boolean validResponse = false;

  while (!validResponse) {
    System.out.println("Do you want to end the program? Please enter yes or no: ");
    response = input.next();
    running = isContinueResponse(response);
    validResponse = isValidResponse(response);

    if (!validResponse) System.out.println("That is an invalid input!");
  }
}