Question

我是Java的初学者，想知道如何读取Java中的对象列表。我有一个问题，要求实现有理数的列表并打印它们（以及其他一些方法）

    import java.util.Scanner;

public class Rational {
    private int a;
    private int b;

    public Rational (int a, int b){
        this.a = a;
        this.b = b;
    }

    @Override
    public String toString() {
        return a + "/" + b;
    }

    public static void main(String []args) throws Exception {
        // Take input from the user in the form of 2 numbers
        Scanner scanner = new Scanner(System.in);

    int n = scanner.nextInt();
    Rational array[] = new Rational[n];

    for(int i=0;i<n;i++) {

        int num = scanner.nextInt();
        int deno = scanner.nextInt();

    // Create a rational obj with 2 args
    Rational array[i] = new Rational(num, deno);
        }
    }
}

所以我试图读取一个对象数组：例如：n = 4然后是第2个3秒5 4 .....

我收到错误提示类型不匹配：无法从Rational转换为理性[]

Answer 1

假设你想从键盘输入信息：

Scanner scanner = new Scanner(System.in);
List<Rational> rationals = new ArrayList<>(); // create a list
String line = scanner.nextLine(); // read list of numbers; e.g., "1/2, 3/4, 7/8"
for (String rational : line.split(",")) { // split string at each ","
    String[] parts = rational.split("/"); // split each of those at "/" character
    rationals.add(new Rational( // parse each half as int; create Rational; add to list
        Integer.parseInt(parts[0].trim()),
        Integer.parseInt(parts[1].trim())));
}

Answer 2

您可以使用类似

的内容

public class Rational {
    private int a;
    private int b;

    public Rational (int a, int b){
        this.a = a;
        this.b = b;
    }

    @Override
    public toString() {
        return a + "/" + b;
    }

    public static void main(String []args) throws Exception {
        // Take input from the user in the form of 2 numbers
        Scanner scanner = new Scanner(System.in);

        int num = scanner.nextInt();
        int deno = scanner.nextInt();

        // Create a rational obj with 2 args
        Rational x = new Rational(num, deno);
        System.out.println(x);
    }
}

读取Java中的对象列表

2 个答案: