From 7dcc3564c93a4ee2471f6dace4aa2bfb695734bc Mon Sep 17 00:00:00 2001
From: liangzejun <liangzejun@szxgl.cn>
Date: Wed, 31 Dec 2025 17:58:51 +0800
Subject: [PATCH] =?UTF-8?q?=E5=88=9D=E5=A7=8B=E5=8C=96=E7=9B=AE=E5=BD=95?=
MIME-Version: 1.0
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---
 01-basics/variables-demo/go.mod  |   3 +
 01-basics/variables-demo/main.go | 133 +++++++++++++++++++++++++++++++
 2 files changed, 136 insertions(+)
 create mode 100644 01-basics/variables-demo/go.mod
 create mode 100644 01-basics/variables-demo/main.go

diff --git a/01-basics/variables-demo/go.mod b/01-basics/variables-demo/go.mod
new file mode 100644
index 0000000..fb4d25e
--- /dev/null
+++ b/01-basics/variables-demo/go.mod
@@ -0,0 +1,3 @@
+module variables-demo
+
+go 1.21
diff --git a/01-basics/variables-demo/main.go b/01-basics/variables-demo/main.go
new file mode 100644
index 0000000..d7a7ef4
--- /dev/null
+++ b/01-basics/variables-demo/main.go
@@ -0,0 +1,133 @@
+package main
+
+import (
+	"fmt"
+	"strconv"
+)
+
+func main() {
+	fmt.Println("=== 变量声明示例 ===")
+
+	// 方式1: 标准声明 可以用于包级别声明
+	var name string = "张三"
+	var age int = 25
+
+	// 方式2: 类型推断 可以用于包级别声明
+	var city = "北京"
+	var score = 95.5
+
+	// 方式3: 短声明（最常用） 不能用于包级别声明
+	email := "test@example.com"
+	isActive := true
+
+	// 方式4: 批量声明
+	var (
+		username = "admin"
+		password = "123456"
+		port     = 8080
+	)
+
+	fmt.Printf("姓名: %s, 年龄: %d, 城市: %s\n", name, age, city)
+	fmt.Printf("分数: %.2f, 邮箱: %s, 激活: %t\n", score, email, isActive)
+	fmt.Printf("用户: %s, 端口: %d\n", username, port)
+	_ = password // 避免未使用变量错误
+
+	fmt.Println("\n=== 数据类型示例 ===")
+
+	// 整数
+	var num int = 100
+	var byte1 uint8 = 255
+
+	// 浮点数
+	var pi float64 = 3.141592653589793
+
+	// 字符串
+	var greeting = "Hello, Go!"
+	multiline := `
+		这是多行字符串
+		保留格式
+	`
+
+	// 布尔值
+	var flag bool = true
+
+	fmt.Printf("整数: %d, 字节: %d\n", num, byte1)
+	fmt.Printf("浮点数: %f\n", pi)
+	fmt.Printf("字符串: %s\n", greeting)
+	fmt.Printf("多行: %s\n", multiline)
+	fmt.Printf("布尔: %t\n", flag)
+
+	fmt.Println("\n=== 常量示例 ===")
+
+	const PI = 3.14159
+	const AppName = "MyApp"
+
+	const (
+		StatusOK       = 200
+		StatusNotFound = 404
+		StatusError    = 500
+	)
+
+	const (
+		Monday    = iota // 0
+		Tuesday          // 1
+		Wednesday        // 2
+		Thursday         // 3
+		Friday           // 4
+	)
+
+	fmt.Printf("常量 PI: %f, App: %s\n", PI, AppName)
+	fmt.Printf("状态码: %d, %d, %d\n", StatusOK, StatusNotFound, StatusError)
+	fmt.Printf("星期: %d, %d, %d\n", Monday, Tuesday, Wednesday)
+
+	fmt.Println("\n=== 类型转换示例 ===")
+
+	// 数值转换
+	var i int = 42
+	var f float64 = float64(i)
+	var u uint = uint(f)
+	fmt.Printf("int: %d -> float64: %f -> uint: %d\n", i, f, u)
+
+	// 字符串与数值转换
+	num2 := 123
+	str := strconv.Itoa(num2)
+	fmt.Printf("int to string: %s (类型: %T)\n", str, str)
+
+	str2 := "456"
+	num3, err := strconv.Atoi(str2)
+	if err != nil {
+		fmt.Println("转换失败:", err)
+	} else {
+		fmt.Printf("string to int: %d (类型: %T)\n", num3, num3)
+	}
+
+	fmt.Println("\n=== 运算符示例 ===")
+
+	a, b := 10, 3
+
+	fmt.Printf("%d + %d = %d\n", a, b, a+b)
+	fmt.Printf("%d - %d = %d\n", a, b, a-b)
+	fmt.Printf("%d * %d = %d\n", a, b, a*b)
+	fmt.Printf("%d / %d = %d\n", a, b, a/b)
+	fmt.Printf("%d %% %d = %d\n", a, b, a%b)
+
+	// 比较运算
+	fmt.Printf("%d == %d: %t\n", a, b, a == b)
+	fmt.Printf("%d > %d: %t\n", a, b, a > b)
+
+	// 逻辑运算
+	t, f2 := true, false
+	fmt.Printf("true && false: %t\n", t && f2)
+	fmt.Printf("true || false: %t\n", t || f2)
+	fmt.Printf("!true: %t\n", !t)
+
+	fmt.Println("\n=== 零值示例 ===")
+
+	var zeroInt int
+	var zeroFloat float64
+	var zeroBool bool
+	var zeroString string
+
+	fmt.Printf("int零值: %d, float零值: %f, bool零值: %t, string零值: '%s'\n",
+		zeroInt, zeroFloat, zeroBool, zeroString)
+}