From f5d6faa31cbcf0658c60d569cdffceb9b81b8caf Mon Sep 17 00:00:00 2001
From: xuxin <840198532@qq.com>
Date: Tue, 23 Dec 2025 15:17:57 +0800
Subject: [PATCH] =?UTF-8?q?java=E4=B8=AD=E7=9A=84=E8=87=AA=E5=8A=A8?=
 =?UTF-8?q?=E8=BD=AC=E6=8D=A2=E6=A6=82=E5=BF=B5=E4=BB=8B=E7=BB=8D?=
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---
 day02/src/com/inmind/Demo01.java | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 day02/src/com/inmind/Demo01.java

diff --git a/day02/src/com/inmind/Demo01.java b/day02/src/com/inmind/Demo01.java
new file mode 100644
index 0000000..f893085
--- /dev/null
+++ b/day02/src/com/inmind/Demo01.java
@@ -0,0 +1,23 @@
+package com.inmind;
+/*
+自动转换：将取值范围小的类型自动提升为取值范围大的类型
+ */
+public class Demo01 {
+    public static void main(String[] args) {
+        //定义2个int变量（4个字节）
+        int a = 10;
+        int b = 20;
+
+        //2个整数相加
+        int sum = a+b;
+        System.out.println(sum);//30
+
+        //定义一个字节型变量（1个字节）
+        byte b1 = 2;
+        int sum1 = a+b1;//先将1字节的b1,自动提升（转换）为4字节的int型，再进行计算的
+        System.out.println(sum1);//12
+
+        //12的整数是可以被一个byte所表示
+        //byte b2 = a+b1;//错误，a+b1发生了自动类型转换，计算之后是一个4字节的int型的值，是不能直接赋值给1字节的类型
+    }
+}