如何將掃描儀輸入與數組進行比較？

Question

我想知道如何比較掃描儀和數組的輸入。 很抱歉，如果這是一個簡單的問題，但我對Java很新。

這是我寫的：

    public static void handleProjectSelection() {

    Scanner getProjectNum = new Scanner(System.in);
    int answer;
    int[] acceptedInput = {1, 2, 3};//The only integers that are allowed to be entered by the user.


    System.out.println("Hello! Welcome to the program! Please choose which project" +
    "you wish to execute\nusing keys 1, 2, or 3.");
    answer = getProjectNum.nextInt(); //get input from user, and save to integer, answer.
        if(answer != acceptedInput[]) {
            System.out.println("Sorry, that project doesn't exist! Please try again!");
            handleProjectSelection();//null selection, send him back, to try again.
        }

}

我希望用戶只能輸入1,2或3。

任何幫助，將不勝感激。

謝謝。

Answer 1

你可以使用這個功能：

public static boolean isValidInput(int input, int[] acceptedInput) {
    for (int val : acceptedInput) { //Iterate through the accepted inputs
        if (input == val) {
            return true;
        }
    }
    return false;
}

請注意，如果您正在使用字符串，則應使用此字符：

public static boolean isValidInput(String input, String[] acceptedInput) {
    for (String val : acceptedInput) { //Iterate through the accepted inputs
        if (val.equals(input)) {
            return true;
        }
    }
    return false;
}

Answer 2

您可以使用Arrays類中的二進制搜索，它將為您提供給定整數的索引位置。

樣品：

 if(Arrays.binarySearch(acceptedInput , answer ) < 0)  {
        System.out.println("Sorry, that project doesn't exist! Please try again!");
        handleProjectSelection();//null selection, send him back, to try again.
 }

如果結果為負，則answer不在您的數組中