上面的Java读行

Question

我需要保存由这段代码随机生成的数字。

import com.sun.org.apache.bcel.internal.generic.GOTO;

import java.io.BufferedReader;
import java.io.StringReader;
import java.util.Arrays;
import java.util.Random;
import java.util.Scanner;

import static java.lang.System.exit;

class Main {
    public static void main(String[] args) {
        int chose;
        int[] card = new int[9];
        int[] pin_save = new int[4];
        System.out.println("1. Create an account");
        System.out.println("2. Log into account");
        System.out.println("0. Exit");

        Scanner scanner = new Scanner(System.in);
        chose = scanner.nextInt();

        switch (chose) {
            case 1:
                //generate card

                System.out.println("Your card has been created");
                System.out.print("Your card number is:" + System.lineSeparator() + "400000");
                Random random = new Random();


                for (int i = 0; i < card.length; i++) {
                    int n = random.nextInt(10);
    //                    for (int a = 0; a < card.length; a++){
    //                        card[a] = n;
    //                    }
                    System.out.print(n);
                }

                //System.out.println("400000" + java.util.Arrays.toString(card));
                System.out.println(System.lineSeparator() + "Your card PIN:");

                for (int j = 0; j < pin_save.length; j++) {
                    int pin = random.nextInt(10);
                    for (int p = 0; p < pin_save.length; p++) {
                        pin_save[p] = pin;
                    }
                    System.out.print(pin);
                    //System.out.println(pin_save);
                }
                break;

            case 2:
                //login
                System.out.println("Your card number is: ");
                System.out.print("400000" + card);
                System.out.println("Your PIN is: ");
                System.out.print(pin_save);
                break;
            case 0:
                System.out.println("Bye!");
                break;
        }
    }
}

示例输出是：

Your card has been created
Your card number is:
4000008273821792
Your card PIN:
4826

我应该使用什么来保存卡号和密码? 400000是不变的，所以我真正需要的是第二部分。有什么想法吗？

Answer 1

例如，将它们存储到String，中：

  String lastCardNumbers="";

  for (int i = 0; i < card.length; i++) 
  {
      int n = random.nextInt(10);
      lastCardNumbers+=n;
      System.out.print(n);
  }

变量lastCardNumbers将存储最后一个数字，因为它转换值并将它们附加到字符串中。你的系统应该看起来就像

System.out.print("400000" + lastCardNumbers);

或者，您可以避免将它们转换并存储到array中。

  int[] lastCardNumbers = new int[card.length];

  for (int i = 0; i < card.length; i++) 
  {
      lastCardNumbers[i]= random.nextInt(10);
      System.out.print(lastCardNumbers[i]);
  }