From 9b7256f72412d31fe2aa444d0244c68fcfeed957 Mon Sep 17 00:00:00 2001
From: xuxin <840198532@qq.com>
Date: Mon, 14 Sep 2026 16:26:52 +0800
Subject: [PATCH] =?UTF-8?q?day01--java=E4=B8=AD=E7=9A=84=E5=8F=98=E9=87=8F?=
 =?UTF-8?q?=E5=92=8C=E6=95=B0=E6=8D=AE=E7=B1=BB=E5=9E=8B=E6=A6=82=E8=BF=B0?=
 =?UTF-8?q?-=E8=A1=A5=E5=85=85?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 day01/src/com/inmind/Demo02.java | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/day01/src/com/inmind/Demo02.java b/day01/src/com/inmind/Demo02.java
index da8a906..977d9e9 100644
--- a/day01/src/com/inmind/Demo02.java
+++ b/day01/src/com/inmind/Demo02.java
@@ -20,7 +20,7 @@ Java的数据类型分为两大类：
 
 Java中的默认类型：整数类型是int 、浮点类型是double
  */
-public class Demo02 {
+public class Demo02 {//定义一个类，类是有范围
 
     //psvm:主方法的快捷方式
     public static void main(String[] args) {//程序主入口
@@ -38,21 +38,27 @@ public class Demo02 {
         long l = 20000000000L;
         System.out.println(l);
         //定义float类型的变量(注意：java中只要是小数默认是double类型，如果要表示单精度型，必须在后面加f或F)
-        float f = 1.1f;
+        float f = 1.1F;
         System.out.println(f);
         //定义double类型的变量
         double d = 1.1;
         System.out.println(d);
         //定义char类型的变量
-        char c = 'x';
+        char c = '中';
         System.out.println(c);
         //定义boolean类型的变量
-        boolean b2 = true;
+        boolean b2 = false;
         System.out.println(b2);
 
         //扩展，定义字符串类型的变量
         String str = "abc";
         System.out.println(str);
+
+        //一个变量定义好后，是可以修改
+        str = "这是修改后的值";
+        System.out.println(str);
+        //在java中同一个范围内，变量名不能重复,{}就是范围
+        int i1 = 100;
     }
 
 }