如何打破这个 while(true) 循环？

Question

嗨，我试图打破这个循环并在两个 if 语句都为真时返回坐标。 然而，循环永远不会结束。 我该如何解决？

public static String[] positionQuery(int dim, Scanner test_in) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("Provide origin and destination coordinates.");
        System.out.println("Enter two positions between A1-H8:");
        while(true) {
            String line = scanner.nextLine();
            String[] coordinates = line.split(" ");
            if(coordinates.length == 2) {
                String origin = coordinates[0];
                String dest = coordinates[1];
                if(validCoordinate(origin, dim) && validCoordinate(dest,dim)) {
                    return coordinates;
                }
            }
            System.out.println("ERROR: Please enter valid coordinate pair separated by space.");
        }
    }

我想我对 validCoordinates 有问题，因为我只对 validCoordinates 进行了验证，但找不到我做错了什么。

public static boolean validCoordinate(String coordinate, int dimension) {
        boolean isValidCoordinate;
        String [] alphabet = {"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
        int [] numbers = new int [dimension];
        int one = 1;
        for(int i = 0; i < dimension; i++){
            numbers[i] = one + i;
        }
        for(int i = 0; i < dimension; i++){
            if((Character.toString(coordinate.charAt(0))).contains(alphabet[i])) {
                for(int j = 0; j < dimension; j++) {
                    if ((coordinate.substring(1)).contains(Integer.toString(numbers[j]))) {
                        return true;
                    }
                }
            }
        }

        return false;
    }

Answer 1

嗨，我试图打破这个循环，当两个if语句都为true时返回坐标。 但是，循环永远不会结束。 我该如何解决？

public static String[] positionQuery(int dim, Scanner test_in) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("Provide origin and destination coordinates.");
        System.out.println("Enter two positions between A1-H8:");
        while(true) {
            String line = scanner.nextLine();
            String[] coordinates = line.split(" ");
            if(coordinates.length == 2) {
                String origin = coordinates[0];
                String dest = coordinates[1];
                if(validCoordinate(origin, dim) && validCoordinate(dest,dim)) {
                    return coordinates;
                }
            }
            System.out.println("ERROR: Please enter valid coordinate pair separated by space.");
        }
    }

我想我对validCoordinates有问题，因为我只是对validCoordinates有所了解，但找不到我做错了什么。

public static boolean validCoordinate(String coordinate, int dimension) {
        boolean isValidCoordinate;
        String [] alphabet = {"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
        int [] numbers = new int [dimension];
        int one = 1;
        for(int i = 0; i < dimension; i++){
            numbers[i] = one + i;
        }
        for(int i = 0; i < dimension; i++){
            if((Character.toString(coordinate.charAt(0))).contains(alphabet[i])) {
                for(int j = 0; j < dimension; j++) {
                    if ((coordinate.substring(1)).contains(Integer.toString(numbers[j]))) {
                        return true;
                    }
                }
            }
        }

        return false;
    }

Answer 2

您的有效坐标不正确，它只检查由字母数组中的维度参数指定的前几个值。

尝试这个

public static boolean validCoordinate(String coordinate, int dimension) {
        boolean isValidCoordinate;
        String [] alphabet = {"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
        int [] numbers = new int [dimension];
        for(int i = 0; i < dimension; i++){
            numbers[i] = 1 + i;
        }
        if(Arrays.asList(alphabet).contains(Character.toString(coordinate.charAt(0)))) {
            for(int j = 0; j < dimension; j++) {
              if ((coordinate.substring(1)).contains(Integer.toString(numbers[j]))) {
                  return true;
              }
            }
        }
        return false;
    }

您绝对可以改进此代码，我会将其作为挑战留给您。

这是相关的 repl https://repl.it/@Blakeinstein/question60251495

忍者编辑：我建议你修改你的位置查询

public static String[] positionQuery(int dim) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("Provide origin and destination coordinates.");
        System.out.println("Enter two positions between A1-H8:");
        while(true) {
            String line = scanner.nextLine();
            String[] coordinates = line.split(" ");
            if(coordinates.length == 2) {
                String origin = coordinates[0];
                String dest = coordinates[1];
                if(validCoordinate(origin, dim) && validCoordinate(dest,dim)) {
                    return coordinates;
                }
                else{
                  System.out.println("Coordinates are not valid");
                }
            }
            else{
              System.out.println("ERROR: Please enter valid coordinate pair separated by space.");
            }
        }
    }