如何在名字和姓氏之間加上空格

Question

我不知道爲什麼我的姓氏和名字在它們之間沒有空格的情況下打印。請幫忙！

import java.util.Scanner; 

public class LastNameFirstNameChapter3 
{ 
    public static void main(String[] args) 
    { 
    Scanner stdIn = new Scanner(System.in); 
    String firstName; // Users First Name 
    String lastName; // Users Last Name 
    String age;   // Users Age 

    System.out.print("Enter Your First Name: "); 
    firstName = stdIn.nextLine(); 
    System.out.println("Hello " +""+ firstName + "!"); 
    System.out.print("Please Enter Your Last Name: "); 
    lastName = stdIn.nextLine(); 
    System.out.println("Hello " + firstName +""+ lastName + "!"); 
    System.out.print("Enter Your Age: "); 
    age = stdIn.nextLine(); 
    } // end main 
}  // end class LastNameFirstNameChapter3 

Answer 1

import java.util.Scanner; 

public class LastNameFirstNameChapter3 
{ 
    public static void main(String[] args) 
    { 
    Scanner stdIn = new Scanner(System.in); 
    String firstName; // Users First Name 
    String lastName; // Users Last Name 
    String age;   // Users Age 

    System.out.print("Enter Your First Name: "); 
    firstName = stdIn.nextLine(); 
    System.out.println("Hello " +" "+ firstName + "!"); 
    System.out.print("Please Enter Your Last Name: "); 
    lastName = stdIn.nextLine(); 
    System.out.println("Hello " + firstName +" "+ lastName + "!"); 
    System.out.print("Enter Your Age: "); 
    age = stdIn.nextLine(); 
    } // end main 
}