From 9f9a101b694808e72e11da0d2a817b329e471c4b Mon Sep 17 00:00:00 2001
From: xuxin <840198532@qq.com>
Date: Wed, 15 Jul 2026 15:52:05 +0800
Subject: [PATCH] =?UTF-8?q?day02-=E6=95=B0=E6=8D=AE=E7=B1=BB=E5=9E=8B?=
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---
 day02/src/com/inmind/datatype/Demo02.java | 25 +++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 day02/src/com/inmind/datatype/Demo02.java

diff --git a/day02/src/com/inmind/datatype/Demo02.java b/day02/src/com/inmind/datatype/Demo02.java
new file mode 100644
index 0000000..d710b77
--- /dev/null
+++ b/day02/src/com/inmind/datatype/Demo02.java
@@ -0,0 +1,25 @@
+package com.inmind.datatype;
+/*
+注意：范围小的类型向范围大的类型提升，byte、short、char 运算时直接提升为int
+byte、short、char-->int-->long-->float-->double
+
+ */
+public class Demo02 {
+    public static void main(String[] args) {
+        //定义一个byte类型的变量
+        byte b = 1;
+        short s = 2;
+        //short sum = b+s;//错误，此时b和s都自动提升为int型，无法赋值给short型变量
+        int sum = b+s;
+
+        //定义长整型的变量
+        long l = 3L;
+        long l1 = l+sum;//能，sum发生了自动类型转换，自动转换为long型
+        System.out.println(l1);
+
+        //定义一个双精度的浮点型变量
+        double d = 3.15;
+        double sum1 = d+l;//能，l发生了自动类型转换，自动转换为double型
+        System.out.println(sum1);
+    }
+}