java - 随机用户名生成器，带有错误背后的随机数

Question

我已经研究了大约一个小时，我真的无法弄清楚这一点，我想制作一些提示并读取用户的名字和姓氏(分别)的东西。然后打印一个由用户名字的第一个字母、用户姓氏的前五个字符和 10 到 99 范围内的随机数组成的字符串。并假设姓氏至少有五个字母长

import java.util.Scanner;  //Needed for the Scanner class  
import java.lang.String;

import java.util.Random;

public class UsernameGenerator
{    
public static void main(String[] args)  //all the action happens here!    
{  Scanner input = new Scanner (System.in);
    Random generator = new Random();

    int num1;
    num1 = generator.nextInt(10-99);

    String firstName;
    String lastName;
    String concatenatedName;

    System.out.println("Enter your First Name: ");
    firstName = input.next();



    System.out.print( "Enter your Last Name: " );
    lastName = input.next();


    // We'll take the first character in the first name
    concatenatedName = firstName.charAt(0) + lastName.substring(0, 5) + num1;



    Random rnd = new Random(); // Initialize number generator
    if (lastName.length() > 5)
        concatenatedName += lastName.substring(0,5);
    else
        concatenatedName += lastName; // You did not specify what to do, if the name is shorter than 5 chars

    concatenatedName += Integer.toString(rnd.nextInt(99));


    System.out.println();

}
}

Answer 1

您应该尝试类似的方法来处理姓氏长度可能不是 5 个字符的事实。函数的后半部分 - 不需要设置检查长度并添加另一个随机数。

    // We'll take the first character in the first name
    try
    {
        concatenatedName = firstName.charAt(0) + lastName.substring(0, 5) + num1;
    }
    catch (Exception e)
    {
        // Here we deal with the fact we might not be able to get 5 characters from the last name
        // - Just add the full lastname
        concatenatedName = firstName.charAt(0) + lastName + num1;
    }

    System.out.println(concatenatedName);