Question

有人可以帮我吗？我需要的只是帮助。我尝试使用while循环，这似乎不起作用。基本上，为了更清楚，我需要让用户输入int 0 - 9的值.2 if语句查找负数和outofbound数。我想要的是重复代码，直到输入正确的输入。如果用户输入是char。enter code here

，也是同样的事情

public static void doUserMove(Scanner console, char[][] board) 
{
    do
    {
        System.out.print("Which row from 0-9 do you want to place your character: ");
        int row = console.nextInt();
        if(row >= SIZE)
        {
            System.out.print("Your row is OUT-OF-BOUND! Please enter a number from 0 to 9: ");

            System.out.println();
        }

        else if(row < 0)
        {
            System.out.print("Your row is NEGATIVE! Please enter NON-NEGATIVE number from 0 to 9: ");

            System.out.println();
        }

        System.out.print("Which column from 0-9 do you want to place your character: ");
        int column = console.nextInt();

        if(column >= SIZE)
        {
            System.out.println("Your column is OUT-OF-BOUND! Please enter a number from 0 to 9");
            System.out.println();
        }

        else if(column < 0)
        {

            System.out.println("Your column is NEGATIVE! Please enter NON-NEGATIVE number from 0 to 9!");
            System.out.println();
        }

        else if(board[row][column] != ' ')
        {

            System.out.println("FCFS: First Come For Serve! Please enter another position.");
            System.out.println();
        }

        else
        {
            board[row][column] = 'U';
            return;
        }

    }
    while(true);
}

Answer 1

使用while循环是正确的方法，只需尝试这样（每个变量一个循环）：

int row;
do {
   System.out.printline("please input number");
   row = console.nextInt();
} while(row > size || row < 0)

这样，它一直询问直到行在允许的范围内。或者，您可以首先询问不同的文本，然后运行while循环，说输入无效（这样用户就知道他做错了）

Answer 2

您可以尝试这样的事情：

public static void main(String[] args) {

    do {
        System.out.print("Which row from 0-9 do you want to place your character: ");
        int row = getValue(new Condition(MIN, MAX));

        System.out.print("Which column from 0-9 do you want to place your character: ");
        int column = getValue(new Condition(MIN, MAX));
    } while (true);

}

private static int getValue(Condition condition) {
    Scanner scanner = new Scanner(System.in);
    int value;
    do {
        value = scanner.nextInt();
        if (value < condition.min || value > condition.max) {
            System.out.println("Your enter is OUT-OF-RANGE! Please enter a number from "+condition.min+" to "+condition.max+": ");
        }
    } while (value < condition.min || value > condition.max);
    return value;
}

class Condition {
    int min;
    int max;

    public Condition(int min, int max) {
        this.max = max;
        this.min = min;
    }
}

Answer 3

Try-catch也应该有用！

public static void doUserMove(Scanner console, char[][] board) {
    System.out.print("Which row from 0-9 do you want to place your character: ");
    int row = console.nextInt();

    System.out.print("Which column from 0-9 do you want to place your character: ");
    int column = console.nextInt();

    try {

        if(board[row][column] != ' ') {
            System.out.println("FCFS: First Come For Serve! Please enter another position.");
        } else {
            board[row][column] = 'U';
        }

    } catch (ArrayIndexOutOfBoundsException e) {
        System.out.println("Sorry, your row and/or column is out of bounds! Please try again");
        doUserMove(console, board);
    }
}

如果此代码不起作用，请告诉我！

连续请求输入，直到右输入在java中有效

3 个答案: