java - 你如何在 Java 中从大写变成小写，我的代码输出有问题

Question

在这个 starwars 名称生成器代码中，我得到的输出是:

May the force be with you, PatSm BaSan

什么时候应该:

May the force be with you, Patsm Basan.

这是我的代码供引用。

import java.util.Locale;
import java.util.Scanner;

public class Assignment2 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.printf("Enter your first name: ");
        String firstname = input.nextLine().substring(0,3); 
        firstname = firstname.substring(0,1).toUpperCase() + firstname.substring(1).toLowerCase();

        System.out.printf("Enter your last name: ");
        String lastname = input.nextLine().substring(0,2);
        lastname = lastname.substring(0,1).toUpperCase() + lastname.substring(1).toLowerCase(); 

        System.out.printf("Enter your mother's maiden name: ");
        String mothersname = input.nextLine();
        mothersname = mothersname.substring(0,2);

        System.out.printf("Enter the name of the city in which you were born: ");
        String cityname = input.nextLine();
        cityname = cityname.substring(0,3);

        String StarWarsName = firstname+lastname+" "+mothersname+cityname;
        System.out.println("May the force be with you, " + StarWarsName );
    }
}

Answer 1

通过在姓氏的第一个字母上使用 toUpperCase() 使姓氏以大写字母开头。

您可以轻松修复变量 StarWarsName 的大小写。尝试:

String correctName = "";
for (int i = 0; i < starWarsName.length(); i++) {
   if (i == 0 || starWarsName.charAt(i - 1) == ' ')
       correctName += starWarsName.substring(i, i + 1).toUpperCase();
   else
       correctName += starWarsName.substring(i, i + 1).toLowerCase();
}

此外，变量名应该以小写字母开头。 ;)