Scanner.scan /初始化变量

Question

我有一个简单的小问题，我需要从scanner.scan中读取变量“age”，其中用户输入一个数字。它一直告诉我初始化它，但为了做到这一点，我需要为变量提供一个整数，我不想这样做。我怎么能解决这个问题？

import java.util.*; 

import java.io.*; 

import java.util.Scanner; 

public class Person 

{ 

    public static void main(String[]args) 

    { 

    int age; 

    Scanner scan = new Scanner(System.in); 

    System.out.println("Enter in your age."); 

    if (age < 18) 

    { 
     System.out.println("Youth is a beautiful thing."); 
    } 

    else 

    { 
     System.out.println("Age is just a state of mind."); 
    } 


} 
} 

Answer 1

您必须阅读age。见下文。

import java.util.*; 
import java.io.*; 
import java.util.Scanner; 
public class Person 
{ 
    public static void main(String[]args) 
    { 
     int age; 
     Scanner scan = new Scanner(System.in); 

     System.out.println("Enter in your age."); 
     age = scan.nextInt(); <---- **//This is what you are missing** 

     if (age < 18) 
     { 
     System.out.println("Youth is a beautiful thing."); 
     } 

     else 
     { 
     System.out.println("Age is just a state of mind."); 
     } 
    } 
} 

Answer 2

您没有阅读age任何地方。为此，在初始化扫描后执行以下操作。

age = scan.nextInt(); 

Answer 3

under System.out.println（“Enter in your age。”）;

age = scan.nextInt();