Question

我想以188/4的形式从用户那里得到一个有理数的例子并以int 188和int 4结束。什么是在java中这样做的有效方法？是stringTokenizer最好的方法吗？或者是否有类似scanf的东西？

private int NUM;
private int DEN;
static Scanner s;
public Rational(){
    s = new Scanner(System.in).useDelimiter("/");
    System.out.println("Enter Rational number in the form of a/b:");
    NUM = s.nextInt();
    int d = s.nextInt();
    if(d == 0){
        throw new IllegalArgumentException();
    }
    else{
        DEN = d;
    }
}

当我运行此程序时，我的程序在输入数字后冻结

Answer 1

尝试这样的事情（假设每个部分可以在一个单独的行上输入）：

        s = new Scanner(System.in).useDelimiter("\n");
        System.out.println("Enter Rational number in the form of a/b:");
        String in = s.nextLine();
        while (in.length() > 0) {
            if (in.contains("/")) {
                try {
                     NUM = Integer.parseInt(in.split("/")[0]);
                     DEN = Integer.parseInt(in.split("/")[1]);
                } catch (Exception e){
                    throw new IllegalArgumentException("Fraction must contain numeric values only");
                }
            } else {
                throw new IllegalArgumentException("Fraction must contain a '/' character");
            }
            System.out.println("NUM = " + NUM + " DEN = " + DEN);
            in = s.nextLine();
        }

Answer 2

小调整......

private int NUM;
private int DEN;
static Scanner s;
public Rational(){
    System.out.println("Enter Rational number in the form of a/b:");
    s = new Scanner(System.in);
    String[] values = s.next().split("/");

    NUM = Integer.parseInt(values[0]);
    int d = Integer.parseInt(values[1]);
    if(d == 0){
        throw new IllegalArgumentException();
    } else{
        DEN = d;
    }
}

Answer 3

我能想到的唯一方法是将其视为字符串，删除不必要的＆＃34; /＆＃34;然后使用Integer.parseInt（）;

将其转回int

  int NUM;
        int DEN;
        Scanner s;
            s = new Scanner(System.in).useDelimiter("/");
            System.out.println("Enter Rational number in the form of a/b:");
            String enteredString = s.nextLine();

            String firstString = "", secondString = "";
            StringBuilder sb = new StringBuilder(enteredString);

            boolean foundWeirdChar = false;
            boolean firstChar = true;
            char tempChar = '/';

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

                if(sb.charAt(i) == tempChar) {
                    foundWeirdChar = true;
                }

                if(!foundWeirdChar) {
                    firstString += sb.charAt(i);
                }else {
                    if(firstChar) { // Because the first char will be "/"
                        firstChar = false;
                    }else{
                     secondString += sb.charAt(i);
                    }
                }
            }
            int a = 0;
            int b = 0;
            try {
                a = Integer.parseInt(firstString);
                b = Integer.parseInt(secondString);

                System.out.println("First int: " + a + "\nSecond int: " + b);

            }catch(NumberFormatException ex) {
                ex.printStackTrace();
            }

从java中的用户输入解析整数？

3 个答案: