Question

我希望在命令提示符下以这种方式输入原始问题（rawQuestions）： java Hangman Hello测试123，进入数组（问题）。我知道rawQuestion不能在＆＃34;存储有效问题到数组＆＃34;部分因为

＆＃34;错误：＆＃39;;＆＃39;预期＆＃34;和＆＃34;错误：不是声明＆＃34;

在

行

＆＃34;问题[vCount] = String rawQuestion; ＆＃34;

因此我该如何重写呢？

public class Hangman {

    //Validation of raw questions

    public static boolean isValidQuestion(String rawQuestion){
        rawQuestion = rawQuestion.toUpperCase();
        boolean vQuestion = true;
        for(int i=0; i<rawQuestion.length(); i++){
            char c = rawQuestion.charAt(i);

            if(!(c>='A' && c<='Z'))
            vQuestion = false;
        }
        return vQuestion;
    }


    public static void main(String args[]){

        boolean vQs[] = new boolean[args.length];

        for(int i=0; i<args.length; i++){

            String rawQuestion = args[i];

            boolean b = isValidQuestion(rawQuestion);

            if(b)
                 System.out.println(rawQuestion + " is a valid question!");

            else
                 System.out.println("Error: " + rawQuestion + ", input must be a word consist of a-z or A-Z");

            vQs[i] = b;
        }

        //count the number of valid questions

        int vCount = 0;
        for(int i=0; i<vQs.length; i++){
            System.out.println(i + " " + vQs[i] );
            if(vQs[i])
                vCount++;
        }
        System.out.println("There are " + vCount + " valid questions");

        //store valid questions into an array

        String questions[] = new String[vCount];
        for(vCount=0; vCount<args.length; vCount++){
            questions[vCount] = String rawQuestion;
            System.out.println( questions[vCount] );


        }

    }
}

Answer 1

试试这个：

String[] validQuestions = Arrays.stream(args)
                                .filter(Hangman::isValidQuestion)
                                .toArray(String[]::new);
int validQuestionCount = validQuestions.length;

但即使没有Streams，您的整个方法也可以在一个for循环中完成，一次计算和收集有效问题，而不是分三个步骤：

List<String> validQuestions = new ArrayList<>();
for (int i = 0; i < args.length; i++)
{
    String rawQuestion = args[i];
    boolean b = isValidQuestion(rawQuestion);
    if (b)
    {
        validQuestions.add(rawQuestion);
        System.out.println(rawQuestion + " is a valid question!");
    }
    else
    {
        System.out.println("Error: " + rawQuestion + ", input must be a word consist of a-z or A-Z");
    }
}

// count the number of valid questions
System.out.println("There are " + validQuestions.size() + " valid questions");

// store valid questions into an array
String questions[] = validQuestions.toArray(new String[validQuestions.size()]);

这样，您不必自己处理索引变量，这很难理解，特别是如果其他人试图阅读它。（特别是vCount的重用对我来说有点可怕）

Java，将字符串存储到数组

1 个答案: