commit e6ee860fd975e57f6fbece83c090fbe6273d5f3a
Author: frank <3224536684@qq.com>
Date:   Wed Mar 1 11:23:26 2023 +0800

    :sparkles: init

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..7689b76
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,29 @@
+### Go template
+# If you prefer the allow list template instead of the deny list, see community template:
+# https://github.com/github/gitignore/blob/main/community/Golang/Go.AllowList.gitignore
+#
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+# Go workspace file
+go.work
+
+.idea
+# .vscode
+app.env
+
+.DS_Store
+*/.DS_Store
\ No newline at end of file
diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000..e3fb8e4
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,7 @@
+{
+    "go.autocompleteUnimportedPackages": true,
+    "go.testFlags": [
+        "-v",
+        "-cover"
+    ]
+}
\ No newline at end of file
diff --git a/README.MD b/README.MD
new file mode 100644
index 0000000..93b7a9c
--- /dev/null
+++ b/README.MD
@@ -0,0 +1,73 @@
+# Go学习
+
+### 编写hello world程序
+- package 必须是 main
+- 方法名必须是 main()
+- 文件名不一定是 main.go
+
+### 和其他语言差异
+- Go中 main 函数不支持任何返回值
+- 通过os.Exit来返回状态
+- main 函数不支持传入参数
+- 通过 os.Args 获取命令行参数
+
+### 编写测试程序
+1. 源码文件以 `_test` 结尾: xxx_test.go
+2. 测试方法名以 Test 开头: func TestXXX(t *testing.T) {...}
+
+
+### 变量赋值
+- 赋值可以自动进行类型推断
+- 在一个赋值语句中可以对多个变量进行同时赋值
+```go
+// 单独赋值
+var a int = 1
+var b int = 1
+
+// 同时赋值
+var (
+	a int = 1
+	b int = 1
+)
+
+// 自动推断
+a := 1
+b := 1
+```
+
+### 基本数据类型
+
+```go
+bool
+string
+int	int8	int16	int32	int64
+uint	uint8	uint16	uint32	uint64	uintptr
+byte // alias for uint8
+rune // alias for int32, represents a Unicode code point
+float32	float64
+complex64	complex128
+```
+
+### 类型转化
+- 与其他编程语言的差异
+  1. Go不允许隐式类型转换
+  2. 别名和原有类型也不能进行隐式类型转换
+
+- 类型的预定义值
+  1. math.MaxInt64
+  2. math.MaxFloat64
+  3. math.MaxUint32
+
+
+### 算术运算符
+- Go语言没有前置的 ++, --, 
+
+
+### 线程和协程 Thread vs. Groutine
+
+1. 创建时默认的 stack (栈) 的大小
+   - JDK5 以后 Java Thread stack 默认为 1M
+   - Groutine 的 stack 初始化大小为 2k
+2. 和 KSE (Kernel Speace Entity) 的对应关系
+   - Java Thread 是 1:1
+   - Groutine 是 M:N
\ No newline at end of file
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..92af0fc
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,5 @@
+module go_study
+
+go 1.20
+
+require github.com/go-playground/assert/v2 v2.2.0
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..1998fd7
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,2 @@
+github.com/go-playground/assert/v2 v2.2.0 h1:JvknZsQTYeFEAhQwI4qEt9cyV5ONwRHC+lYKSsYSR8s=
+github.com/go-playground/assert/v2 v2.2.0/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=
diff --git a/src/c10_func/func_test.go b/src/c10_func/func_test.go
new file mode 100644
index 0000000..1a35e76
--- /dev/null
+++ b/src/c10_func/func_test.go
@@ -0,0 +1,60 @@
+package func_test
+
+import (
+	"fmt"
+	"math/rand"
+	"testing"
+	"time"
+)
+
+// 多返回值函数
+func returnMultiValues() (int, int) {
+	return rand.Intn(10), rand.Intn(20)
+}
+
+// 函数用法之一: 统计执行时间
+func timeSpent(inner func(op int) int) func(op int) int {
+	return func(n int) int {
+		start := time.Now()
+		ret := inner(n)
+		fmt.Println("time spent: ", time.Since(start).Seconds())
+		return ret
+	}
+}
+
+func slowFun(op int) int {
+	time.Sleep(time.Second * 1)
+	return op
+}
+
+func TestFn(t *testing.T) {
+	a, b := returnMultiValues()
+	t.Log(a, b)
+
+	tsSF := timeSpent(slowFun)
+	t.Log(tsSF(10))
+}
+
+// 求和
+func Sum(ops ...int) int {
+	ret := 0
+	for _, op := range ops {
+		ret += op
+	}
+	return ret
+}
+
+func TestVarParam(t *testing.T) {
+	t.Log(Sum(1, 3, 5, 7, 9, 2, 6))
+}
+
+func Clear() {
+	fmt.Println("Clear resources")
+}
+
+// defer 延迟执行 一般用于资源的释放和异常的捕捉
+func TestDefer(t *testing.T) {
+	defer Clear()
+	fmt.Println("Start")
+	panic("program error") //抛出异常
+}
diff --git a/src/c11_customer_type/customer_type_test.go b/src/c11_customer_type/customer_type_test.go
new file mode 100644
index 0000000..b83e93c
--- /dev/null
+++ b/src/c11_customer_type/customer_type_test.go
@@ -0,0 +1,29 @@
+package customer_tpye_test
+
+import (
+	"fmt"
+	"testing"
+	"time"
+)
+
+// 自定义类型
+type IntConv func(op int) int
+
+func timeSpent(inner IntConv) IntConv {
+	return func(n int) int {
+		start := time.Now()
+		ret := inner(n)
+		fmt.Println("time spent: ", time.Since(start).Seconds())
+		return ret
+	}
+}
+
+func slowFun(op int) int {
+	time.Sleep(time.Second * 1)
+	return op
+}
+
+func TestFn(t *testing.T) {
+	tsSF := timeSpent(slowFun)
+	t.Log(tsSF(10))
+}
diff --git a/src/c11_encapsulate/encap_test.go b/src/c11_encapsulate/encap_test.go
new file mode 100644
index 0000000..ebf4c70
--- /dev/null
+++ b/src/c11_encapsulate/encap_test.go
@@ -0,0 +1,48 @@
+package encap_test
+
+import (
+	"fmt"
+	"testing"
+	"unsafe"
+)
+
+type Employee struct {
+	Id   string
+	Name string
+	Age  int
+}
+
+// 指针形式 复用  推荐使用
+func (e *Employee) String() string {
+	fmt.Printf("Address is %x \n", unsafe.Pointer(&e.Name))
+	return fmt.Sprintf("Id: %s, Name: %s, Age: %d", e.Id, e.Name, e.Age)
+}
+
+// 数据复制, 地址变了
+// func (e Employee) String() string {
+// 	fmt.Printf("Address is %x \n", unsafe.Pointer(&e.Name))
+// 	return fmt.Sprintf("Id: %s, Name: %s, Age: %d", e.Id, e.Name, e.Age)
+// }
+
+func TestCreateEmployeeObj(t *testing.T) {
+	e := Employee{"1", "Frank", 20}
+	e1 := Employee{Name: "Mike", Age: 28}
+	e2 := new(Employee) //返回指针
+	e2.Id = "3"
+	e2.Name = "Jack"
+	e2.Age = 32
+
+	t.Log(e)
+	t.Log(e1)
+	t.Log(e1.Id) //空字符串
+	t.Log(e2)
+
+	t.Logf("e is %T", e)
+	t.Logf("e2 is %T", e2)
+}
+
+func TestStructOperations(t *testing.T) {
+	e := Employee{"1", "Frank", 20}
+	fmt.Printf("Address is %x \n", unsafe.Pointer(&e.Name))
+	t.Log(e.String())
+}
diff --git a/src/c11_interface/interface_test.go b/src/c11_interface/interface_test.go
new file mode 100644
index 0000000..4133c15
--- /dev/null
+++ b/src/c11_interface/interface_test.go
@@ -0,0 +1,20 @@
+package interface_test
+
+import "testing"
+
+type Programmer interface {
+	WriteWord() string
+}
+
+type GoProgrammer struct {
+}
+
+func (p *GoProgrammer) WriteWord() string {
+	return "hello world"
+}
+
+func TestClient(t *testing.T) {
+	var p Programmer
+	p = new(GoProgrammer)
+	t.Log(p.WriteWord())
+}
diff --git a/src/c12_extend/extension_test.go b/src/c12_extend/extension_test.go
new file mode 100644
index 0000000..38198b8
--- /dev/null
+++ b/src/c12_extend/extension_test.go
@@ -0,0 +1,68 @@
+package extension_test
+
+import (
+	"fmt"
+	"testing"
+)
+
+// golang是可以实现继承的，但是这种继承并不是严格意义上的继承，
+// golang并不支持继承特性，因而也没有单继承,多继承，重写方法等复杂概念。
+
+type Pet struct {
+}
+
+func (p *Pet) Speak() {
+	fmt.Println("...")
+}
+
+func (p *Pet) SpeakTo(host string) {
+	p.Speak()
+	fmt.Println(host)
+}
+
+// 有名继承
+
+type Dog struct {
+	p *Pet
+}
+
+func (d *Dog) Speak() {
+	fmt.Println("汪汪汪!")
+}
+
+func TestDog(t *testing.T) {
+	dog := new(Dog)
+	dog.Speak()
+	// dog.SpeakTo("Zhang") Dog没有这个方法, 虽然Pet有，但是此时Dog不是匿名继承 ，如果要要调用需要指定继承事指定的名称。
+	dog.p.Speak()
+	dog.p.SpeakTo("Li")
+}
+
+// 匿名继承
+
+type People struct {
+}
+
+func (p *People) ShowA() {
+	fmt.Println("AAA")
+}
+
+func (p *People) ShowB() {
+	fmt.Println("BBB")
+}
+
+type Doctor struct {
+	People
+}
+
+func (p *Doctor) ShowA() {
+	fmt.Println("Doctor AAA")
+}
+
+func TestDoctor(t *testing.T) {
+	d := new(Doctor)
+	d.ShowA()
+	d.ShowB() // 因为Teacher没有ShowB()的方法，此时又匿名继承了People，所以会调到People实现的ShowB方法
+	d.People.ShowA()
+	d.People.ShowB()
+}
diff --git a/src/c12_polymorphism/polymorphism_test.go b/src/c12_polymorphism/polymorphism_test.go
new file mode 100644
index 0000000..b72e0c8
--- /dev/null
+++ b/src/c12_polymorphism/polymorphism_test.go
@@ -0,0 +1,41 @@
+package polymorphism
+
+import (
+	"fmt"
+	"testing"
+)
+
+// 多态
+
+type Code string
+
+type Programmer interface {
+	WriteHelloWorld() Code
+}
+
+type GoProgrammer struct {
+}
+
+func (gp *GoProgrammer) WriteHelloWorld() Code {
+	return "fmt.Println(\"hello world\")"
+}
+
+type JavaProgrammer struct {
+}
+
+func (jp *JavaProgrammer) WriteHelloWorld() Code {
+	return "System.out.Println(\"hello world\")"
+}
+
+func writeFirstProgram(p Programmer) {
+	// %T 输出类型
+	fmt.Printf("%T %v\n", p, p.WriteHelloWorld())
+}
+
+func TestPolymorphism(t *testing.T) {
+	gp := new(GoProgrammer)
+	// gp := &GoProgrammer{}
+	jp := new(JavaProgrammer)
+	writeFirstProgram(gp)
+	writeFirstProgram(jp)
+}
diff --git a/src/c13_empty_interface/empty_interface_test.go b/src/c13_empty_interface/empty_interface_test.go
new file mode 100644
index 0000000..7fe543b
--- /dev/null
+++ b/src/c13_empty_interface/empty_interface_test.go
@@ -0,0 +1,40 @@
+package empty_interface
+
+import (
+	"fmt"
+	"testing"
+)
+
+// 空接口与断言
+// 1.空接口可以表示任何类型
+// 2.通过断言来将空接口转换为制定类型
+
+// 空接口入参
+func DoSomething(p interface{}) {
+	// if i, ok := p.(int); ok {
+	// 	fmt.Println("Integer", i)
+	// 	return
+	// }
+
+	// if s, ok := p.(string); ok {
+	// 	fmt.Println("String", s)
+	// 	return
+	// }
+
+	// fmt.Println("Unknown Type")
+	switch v := p.(type) {
+	case int:
+		fmt.Println("Integer", v)
+	case string:
+		fmt.Println("String", v)
+	default:
+		fmt.Println("Unknown Type")
+	}
+}
+
+// 测试空接口入参断言
+func TestEmptyInterfaceAssertion(t *testing.T) {
+	DoSomething(10)
+	DoSomething("1231")
+	DoSomething(8.88)
+}
diff --git a/src/c14_error_test/error_test.go b/src/c14_error_test/error_test.go
new file mode 100644
index 0000000..528f0b3
--- /dev/null
+++ b/src/c14_error_test/error_test.go
@@ -0,0 +1,45 @@
+package error_test
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+)
+
+/*
+
+	Go的错误机制
+	1.没有异常机制
+	2.error类型实现了error接口
+	3.可以通过 errors.New 来快速创建错误实例
+
+*/
+
+var ErrorLessThanTwo = errors.New("n should be not less than 2")
+var ErrorLargerThenHundred = errors.New("n should be not larger than 100")
+
+func GetFibonacci(n int) ([]int, error) {
+	if n < 2 {
+		return nil, ErrorLessThanTwo
+	}
+	if n > 100 {
+		return nil, ErrorLargerThenHundred
+	}
+	fibList := []int{1, 1}
+	for i := 2; i < n; i++ {
+		fibList = append(fibList, fibList[i-2]+fibList[i-1])
+	}
+	return fibList, nil
+}
+
+func TestGetFibonacci(t *testing.T) {
+	if ret, err := GetFibonacci(-10); err != nil {
+		if err == ErrorLessThanTwo {
+			fmt.Println("It is less.")
+		}
+		t.Error(err)
+	} else {
+		t.Log(ret)
+	}
+
+}
diff --git a/src/c14_panic_recover/panic_recover_test.go b/src/c14_panic_recover/panic_recover_test.go
new file mode 100644
index 0000000..720a970
--- /dev/null
+++ b/src/c14_panic_recover/panic_recover_test.go
@@ -0,0 +1,34 @@
+package panic_recover
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+)
+
+// Let it Crash 往往是恢复不确定性错误的最好方法
+// panic 用于不可以恢复的错误
+// panic 退出前会执行 defer 指定的内容
+
+// os.Exit 退出时不会调用 defer 指定的函数
+// os.Exit 退出时不输出当前调用栈信息
+
+// 常见的错误恢复 recover()
+// 当心 recover 成为"恶魔" 形成僵尸服务进程 导致health check失效
+
+func TestPanicVxExit(t *testing.T) {
+	// defer func ()  {
+	// 	fmt.Println("Finally")
+	// }()
+
+	defer func() {
+		// recover() 错误恢复 小心使用
+		if err := recover(); err != nil {
+			fmt.Println("recovered from ", err)
+		}
+	}()
+	fmt.Println("Start")
+	panic(errors.New("Something wrong!"))
+	// os.Exit(-1)
+	// fmt.Println("end")
+}
diff --git a/src/c15_package_test/package_test.go b/src/c15_package_test/package_test.go
new file mode 100644
index 0000000..51be2c3
--- /dev/null
+++ b/src/c15_package_test/package_test.go
@@ -0,0 +1,18 @@
+package client
+
+import (
+	"go_study/src/c15_package_test/series"
+	"testing"
+)
+
+// 可复用模块 包
+// 基本复用单元  以首字母大写来表明可被包外代码访问
+// 代码的 package 可以和所在的目录不一致
+// 同一目录里的 Go 代码的 package 要保持一致
+
+// 测试复用方法
+func TestPackage(t *testing.T) {
+	t.Log(series.GetFibonacciSeries(5))
+
+	// t.Log(series.getSlice())  // 报错 无法访问
+}
diff --git a/src/c15_package_test/series/my_series.go b/src/c15_package_test/series/my_series.go
new file mode 100644
index 0000000..3686d90
--- /dev/null
+++ b/src/c15_package_test/series/my_series.go
@@ -0,0 +1,14 @@
+package series
+
+// GetFibonacciSeries 实现 斐波那契数列
+func GetFibonacciSeries(n int) []int {
+	fibList := []int{1, 1}
+	for i := 2; i < n; i++ {
+		fibList = append(fibList, fibList[i-2]+fibList[i-1])
+	}
+	return fibList
+}
+
+func getSlice() []int {
+	return []int{1, 2, 3, 4, 5}
+}
diff --git a/src/c16_groutine/groutine_test.go b/src/c16_groutine/groutine_test.go
new file mode 100644
index 0000000..e263797
--- /dev/null
+++ b/src/c16_groutine/groutine_test.go
@@ -0,0 +1,18 @@
+package groutine_test
+
+import (
+	"fmt"
+	"testing"
+	"time"
+)
+
+// 测试协程机制
+func TestGroutine(t *testing.T) {
+	for i := 0; i < 10; i++ {
+		// 协程
+		go func(i int) {
+			fmt.Println(i)
+		}(i)
+	}
+	time.Sleep(time.Millisecond * 50)
+}
diff --git a/src/c17_share_memory/share_mem_test.go b/src/c17_share_memory/share_mem_test.go
new file mode 100644
index 0000000..e4eabf2
--- /dev/null
+++ b/src/c17_share_memory/share_mem_test.go
@@ -0,0 +1,89 @@
+package share_mem
+
+import (
+	"fmt"
+	"sync"
+	"testing"
+	"time"
+)
+
+// 共享内存并发机制
+
+func TestCounter(t *testing.T) {
+	counter := 0
+	for i := 0; i < 5000; i++ {
+		go func() {
+			// 不安全的写法
+			counter++
+		}()
+	}
+	time.Sleep(time.Second * 1)
+	t.Logf("counter= %d", counter) // 得到的结果会小于 5000
+}
+
+// Mutex的使用
+func TestCounterThread(t *testing.T) {
+	var mut sync.Mutex
+	counter := 0
+	for i := 0; i < 5000; i++ {
+		go func() {
+			defer func() {
+				mut.Unlock()
+			}()
+			mut.Lock()
+			counter++
+		}()
+	}
+	time.Sleep(time.Second * 1) //去掉 time.Sleep(), counter的结果不符合预期, 小于 5000
+	t.Logf("counter= %d", counter)
+}
+
+// 利用WaitGroup来确定所有任务是否结束
+func TestCounterWaitGroup(t *testing.T) {
+	var mut sync.Mutex
+	var wg sync.WaitGroup
+	counter := 0
+	for i := 0; i < 5000; i++ {
+		wg.Add(1)
+		go func() {
+			defer func() {
+				mut.Unlock()
+			}()
+			mut.Lock()
+			counter++
+			wg.Done()
+		}()
+	}
+	wg.Wait() //挂起 等待完成
+	t.Logf("counter= %d", counter)
+}
+
+var rwMutex *sync.RWMutex
+var wg *sync.WaitGroup
+
+// 读写锁
+func TestRWMutex(t *testing.T) {
+	rwMutex = new(sync.RWMutex)
+	wg = new(sync.WaitGroup)
+	wg.Add(2)
+	go readData(1)
+	go readData(2)
+
+	wg.Wait()
+	fmt.Println("func finish")
+}
+
+func readData(i int) {
+	defer wg.Done()
+	fmt.Println(i, "start locking!")
+	//  给读操作 上锁
+	rwMutex.RLock()
+	//  读数据
+	fmt.Println(i, "Reading data")
+	//  休眠1s
+	time.Sleep(1 * time.Second)
+	//  读解锁
+	rwMutex.RUnlock()
+	//  打印提示信息
+	fmt.Println(i, "Read over")
+}
diff --git a/src/c18_csp/async_service_test.go b/src/c18_csp/async_service_test.go
new file mode 100644
index 0000000..c22c45b
--- /dev/null
+++ b/src/c18_csp/async_service_test.go
@@ -0,0 +1,41 @@
+package csp_test
+
+import (
+	"fmt"
+	"testing"
+	"time"
+)
+
+func service() string {
+	time.Sleep(time.Millisecond * 50)
+	return "Done"
+}
+
+func otherTask() {
+	fmt.Println("执行一些其他的任务")
+	time.Sleep(time.Millisecond * 100)
+	fmt.Println("任务完成")
+}
+
+func TestService(t *testing.T) {
+	fmt.Println(service())
+	otherTask()
+}
+
+func AsyncService() chan string {
+	retChan := make(chan string, 1) // buffered channel (非阻塞、异步模式) 不会阻塞service
+	// retChan := make(chan string)  // unbuffered channel (阻塞、同步模式) 会阻塞service
+	go func() {
+		ret := service()
+		fmt.Println("返回service结果")
+		retChan <- ret
+		fmt.Println("service已退出")
+	}()
+	return retChan
+}
+
+func TestAsyncService(t *testing.T) {
+	retCh := AsyncService()
+	otherTask()
+	fmt.Println(<-retCh)
+}
diff --git a/src/c19_select/select_test.go b/src/c19_select/select_test.go
new file mode 100644
index 0000000..51b5640
--- /dev/null
+++ b/src/c19_select/select_test.go
@@ -0,0 +1,34 @@
+package select_test
+
+import (
+	"fmt"
+	"testing"
+	"time"
+)
+
+func service() string {
+	time.Sleep(time.Millisecond * 100)
+	return "Done"
+}
+
+func AsyncService() chan string {
+	retChan := make(chan string, 1) // buffered channel (非阻塞、异步模式) 不会阻塞service
+	// retChan := make(chan string)  // unbuffered channel (阻塞、同步模式) 会阻塞service
+	go func() {
+		ret := service()
+		fmt.Println("返回service结果")
+		retChan <- ret
+		fmt.Println("service已退出")
+	}()
+	return retChan
+}
+
+// 多路选择 select 实现超时机制
+func TestSelect(t *testing.T) {
+	select {
+	case ret := <-AsyncService():
+		t.Log(ret)
+	case <-time.After(time.Millisecond * 100):
+		t.Error("超时")
+	}
+}
diff --git a/src/c1_hello_world/hello_world.go b/src/c1_hello_world/hello_world.go
new file mode 100644
index 0000000..860afa0
--- /dev/null
+++ b/src/c1_hello_world/hello_world.go
@@ -0,0 +1,19 @@
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+// Go中 main 函数不支持任何返回值
+// main 函数不支持传入参数
+func main() {
+	// 通过 os.Args 获取命令行参数
+	fmt.Println(os.Args)
+	fmt.Println("Hello Golang!")
+	os.Exit(0) // 通过os.Exit来返回状态
+}
+
+// package 必须是 main
+// 方法名必须是 main()
+// 文件名不一定是 main.go
diff --git a/src/c20_cancel_by_close/cancel_test.go b/src/c20_cancel_by_close/cancel_test.go
new file mode 100644
index 0000000..39b2f48
--- /dev/null
+++ b/src/c20_cancel_by_close/cancel_test.go
@@ -0,0 +1,43 @@
+package cancel_test
+
+import (
+	"fmt"
+	"testing"
+	"time"
+)
+
+func isCancelled(cancelChan chan struct{}) bool {
+	select {
+	case <-cancelChan:
+		return true
+	default:
+		return false
+	}
+}
+
+func cancel1(cancelChan chan struct{}) {
+	cancelChan <- struct{}{}
+}
+
+func cancel2(cancelChan chan struct{}) {
+	close(cancelChan)
+}
+
+// 使用close来取消任务
+func TestCancel(t *testing.T) {
+	cancelChan := make(chan struct{}, 0)
+	for i := 0; i < 5; i++ {
+		go func(i int, cancelChan chan struct{}) {
+			for {
+				if isCancelled(cancelChan) {
+					break
+				}
+				time.Sleep(time.Millisecond * 5)
+			}
+			fmt.Println(i, "Done")
+		}(i, cancelChan)
+	}
+	// cancel1(cancelChan)
+	cancel2(cancelChan)
+	time.Sleep(time.Second * 1)
+}
diff --git a/src/c20_cancel_by_context/cancel_by_context_test.go b/src/c20_cancel_by_context/cancel_by_context_test.go
new file mode 100644
index 0000000..4b33d5c
--- /dev/null
+++ b/src/c20_cancel_by_context/cancel_by_context_test.go
@@ -0,0 +1,35 @@
+package cancel_by_context_test
+
+import (
+	"context"
+	"fmt"
+	"testing"
+	"time"
+)
+
+func isCancelled(ctx context.Context) bool {
+	select {
+	case <-ctx.Done():
+		return true
+	default:
+		return false
+	}
+}
+
+// 使用context来取消任务
+func TestCancel(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	for i := 0; i < 5; i++ {
+		go func(i int, ctx context.Context) {
+			for {
+				if isCancelled(ctx) {
+					break
+				}
+				time.Sleep(time.Millisecond * 5)
+			}
+			fmt.Println(i, "Done")
+		}(i, ctx)
+	}
+	cancel()
+	time.Sleep(time.Second * 1)
+}
diff --git a/src/c20_channel_close/channel_close_test.go b/src/c20_channel_close/channel_close_test.go
new file mode 100644
index 0000000..6ff846a
--- /dev/null
+++ b/src/c20_channel_close/channel_close_test.go
@@ -0,0 +1,56 @@
+package channel_close_test
+
+import (
+	"fmt"
+	"sync"
+	"testing"
+)
+
+// 生产者
+func dataProducer(ch chan int, wg *sync.WaitGroup) {
+	go func() {
+		for i := 0; i < 10; i++ {
+			ch <- i
+		}
+		close(ch) // 关闭channel
+		wg.Done()
+	}()
+}
+
+// 消费者
+// func dataReceiver(ch chan int, wg *sync.WaitGroup) {
+// 	go func() {
+// 		for i := 0; i < 10; i++ {
+// 			data := <-ch
+// 			fmt.Println(data)
+// 		}
+// 		wg.Done()
+// 	}()
+// }
+
+func dataReceiver(ch chan int, wg *sync.WaitGroup) {
+	go func() {
+		for {
+			if data, ok := <-ch; ok {
+				fmt.Println(data)
+			} else {
+				// 通道关闭 去获取值会立即返回通道定义类型的默认值
+				fmt.Println(data)
+				break
+			}
+		}
+		wg.Done()
+	}()
+}
+
+func TestCloseChannel(t *testing.T) {
+	var wg sync.WaitGroup
+	ch := make(chan int)
+	wg.Add(1)
+	dataProducer(ch, &wg)
+	wg.Add(1)
+	dataReceiver(ch, &wg)
+	wg.Add(1)
+	dataReceiver(ch, &wg)
+	wg.Wait()
+}
diff --git a/src/c21_singleton/once_test.go b/src/c21_singleton/once_test.go
new file mode 100644
index 0000000..5f610c9
--- /dev/null
+++ b/src/c21_singleton/once_test.go
@@ -0,0 +1,37 @@
+package once_test
+
+import (
+	"fmt"
+	"sync"
+	"testing"
+	"unsafe"
+)
+
+// 利用sync.Once实现 单例模式
+
+type Singleton struct {
+}
+
+var singletonInstance *Singleton
+var once sync.Once
+
+func GetSingletonObj() *Singleton {
+	once.Do(func() {
+		fmt.Println("创建对象")
+		singletonInstance = new(Singleton)
+	})
+	return singletonInstance
+}
+
+func TestGetSingletonObj(t *testing.T) {
+	var wg sync.WaitGroup
+	for i := 0; i < 10; i++ {
+		wg.Add(1)
+		go func() {
+			obj := GetSingletonObj()
+			t.Logf("%x", unsafe.Pointer(obj))
+			wg.Done()
+		}()
+	}
+	wg.Wait()
+}
diff --git a/src/c22_util_anyone_reply/first_response_test.go b/src/c22_util_anyone_reply/first_response_test.go
new file mode 100644
index 0000000..9417d5b
--- /dev/null
+++ b/src/c22_util_anyone_reply/first_response_test.go
@@ -0,0 +1,33 @@
+package util_anyone_reply
+
+import (
+	"fmt"
+	"runtime"
+	"testing"
+	"time"
+)
+
+func runTask(id int) string {
+	time.Sleep(time.Millisecond * 10)
+	return fmt.Sprintf("结果来自: %d", id)
+}
+
+func FirstResponse() string {
+	numOfRunner := 10
+	// 使用 buffered channel (非阻塞、异步模式) 来防止协程泄露
+	ch := make(chan string, numOfRunner)
+	for i := 0; i < numOfRunner; i++ {
+		go func(i int) {
+			ret := runTask(i)
+			ch <- ret
+		}(i)
+	}
+	return <-ch
+}
+
+func TestFirstResponse(t *testing.T) {
+	t.Log("Before 当前系统协程数: ", runtime.NumGoroutine())
+	t.Log(FirstResponse())
+	time.Sleep(time.Second * 1)
+	t.Log("After 当前协程数: ", runtime.NumGoroutine())
+}
diff --git a/src/c23_util_all_done/all_done_test.go b/src/c23_util_all_done/all_done_test.go
new file mode 100644
index 0000000..ef9834a
--- /dev/null
+++ b/src/c23_util_all_done/all_done_test.go
@@ -0,0 +1,36 @@
+package util_all_done
+
+import (
+	"fmt"
+	"runtime"
+	"testing"
+	"time"
+)
+
+func runTask(id int) string {
+	time.Sleep(time.Millisecond * 10)
+	return fmt.Sprintf("结果来自: %d", id)
+}
+
+func AllResponse() string {
+	numOfRunner := 10
+	ch := make(chan string, numOfRunner)
+	for i := 0; i < numOfRunner; i++ {
+		go func(i int) {
+			ret := runTask(i)
+			ch <- ret
+		}(i)
+	}
+	finalRet := ""
+	for j := 0; j < numOfRunner; j++ {
+		finalRet += <-ch + "\n"
+	}
+	return finalRet
+}
+
+func TestAllResponse(t *testing.T) {
+	t.Log("Before 当前系统协程数: ", runtime.NumGoroutine())
+	t.Log(AllResponse())
+	time.Sleep(time.Second * 1)
+	t.Log("After 当前协程数: ", runtime.NumGoroutine())
+}
diff --git a/src/c24_obj_pool/obj_pool.go b/src/c24_obj_pool/obj_pool.go
new file mode 100644
index 0000000..ac7d1de
--- /dev/null
+++ b/src/c24_obj_pool/obj_pool.go
@@ -0,0 +1,42 @@
+package obj_pool
+
+import (
+	"errors"
+	"time"
+)
+
+type MyObj struct {
+}
+
+type ObjPool struct {
+	buffChan chan *MyObj
+}
+
+// 利用channel实现的对象池
+
+func NewObjPool(num int) *ObjPool {
+	objPool := ObjPool{}
+	objPool.buffChan = make(chan *MyObj, num)
+	for i := 0; i < num; i++ {
+		objPool.buffChan <- &MyObj{}
+	}
+	return &objPool
+}
+
+func (p *ObjPool) GetObj(timeout time.Duration) (*MyObj, error) {
+	select {
+	case ret := <-p.buffChan:
+		return ret, nil
+	case <-time.After(timeout): // 超时控制
+		return nil, errors.New("超时")
+	}
+}
+
+func (p *ObjPool) PutObj(obj *MyObj) error {
+	select {
+	case p.buffChan <- obj:
+		return nil
+	default:
+		return errors.New("超出对象池最大容量")
+	}
+}
diff --git a/src/c24_obj_pool/obj_pool_test.go b/src/c24_obj_pool/obj_pool_test.go
new file mode 100644
index 0000000..b93e9d3
--- /dev/null
+++ b/src/c24_obj_pool/obj_pool_test.go
@@ -0,0 +1,27 @@
+package obj_pool
+
+import (
+	"fmt"
+	"testing"
+	"time"
+)
+
+func TestObjPool(t *testing.T) {
+	num := 10
+	pool := NewObjPool(num)
+	//if err := pool.PutObj(&MyObj{}); err != nil { // 尝试防止超出池大小的对象
+	//	t.Error(err)
+	//}
+	for i := 0; i < num; i++ {
+		if obj, err := pool.GetObj(time.Second * 1); err != nil {
+			t.Error(err)
+		} else {
+			fmt.Printf("%T\n", obj)
+			if err := pool.PutObj(obj); err != nil {
+				t.Error(err)
+			}
+		}
+	}
+
+	t.Log("Done.")
+}
diff --git a/src/c25_obj_cache/README.MD b/src/c25_obj_cache/README.MD
new file mode 100644
index 0000000..871178d
--- /dev/null
+++ b/src/c25_obj_cache/README.MD
@@ -0,0 +1,22 @@
+### sync.Pool 对象获取
+
+- 尝试从私有对象获取
+- 私有对象不存在, 尝试从当前Processor的共享池获取
+- 如果当前Processor共享池也是空的,那么就尝试去其他Processor的共享池获取
+- 如果所有子池都是空的, 最后就用用户指定的New函数产生一个新的对象返回
+
+### sync.Pool 对象的生命周期
+
+- GC会清除sync.pool缓存的对象
+- 对象的缓存有效期为下一次GC之前
+
+### sync.Pool对象的放回
+
+- 如果私有对象不存在则保存为私有对象
+- 如果私有对象存在, 放入当前Processor子池的共享池中
+
+### sync.Pool总结
+
+- 适合于通过复用, 降低复杂对象的创建和GC代价
+- 协程安全, 会有锁的开销
+- 生命周期受GC影响, 不适合于做连接池等, 需自己管理生命周期的资源的池化
\ No newline at end of file
diff --git a/src/c25_obj_cache/sync_pool_test.go b/src/c25_obj_cache/sync_pool_test.go
new file mode 100644
index 0000000..80dd8a7
--- /dev/null
+++ b/src/c25_obj_cache/sync_pool_test.go
@@ -0,0 +1,51 @@
+package obj_cache
+
+import (
+	"runtime"
+	"sync"
+	"testing"
+)
+
+func TestSyncPool(t *testing.T) {
+	pool := &sync.Pool{
+		New: func() interface{} {
+			t.Log("Create a new object.")
+			return 100
+		},
+	}
+
+	v := pool.Get().(int)
+	t.Log(v)
+	pool.Put(3)
+
+	v1 := pool.Get().(int)
+	t.Log("put操作后: ", v1)
+	runtime.GC() // GC 会清除sync.pool中缓存的对象
+	v2, _ := pool.Get().(int)
+	t.Log("GC操作后: ", v2)
+
+}
+
+// 协程测试
+func TestSyncPoolInMultiGroutine(t *testing.T) {
+	pool := &sync.Pool{
+		New: func() interface{} {
+			t.Log("create object")
+			return 10
+		},
+	}
+
+	pool.Put(100)
+	pool.Put(100)
+	pool.Put(100)
+
+	var wg sync.WaitGroup
+	for i := 0; i < 10; i++ {
+		wg.Add(1)
+		go func(id int) {
+			t.Log("从pool获取对象: ", pool.Get())
+			wg.Done()
+		}(i)
+	}
+	wg.Wait()
+}
diff --git a/src/c26_unit_test/functions.go b/src/c26_unit_test/functions.go
new file mode 100644
index 0000000..280c39d
--- /dev/null
+++ b/src/c26_unit_test/functions.go
@@ -0,0 +1,5 @@
+package unit_test
+
+func Square(i int) int {
+	return i * i
+}
diff --git a/src/c26_unit_test/functions_test.go b/src/c26_unit_test/functions_test.go
new file mode 100644
index 0000000..9657a9b
--- /dev/null
+++ b/src/c26_unit_test/functions_test.go
@@ -0,0 +1,46 @@
+package unit_test
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/go-playground/assert/v2"
+)
+
+// 表格测试法
+func TestSquare(t *testing.T) {
+	// 输入值
+	inputs := [...]int{1, 2, 3}
+	// 期待值
+	expected := [...]int{1, 4, 9}
+	for i := 0; i < len(inputs); i++ {
+		ret := Square(inputs[i])
+		if ret != expected[i] {
+			t.Errorf("input is %d, the expected is %d, the actual %d", inputs[i], expected[i], ret)
+		}
+	}
+}
+
+func TestErrorInCode(t *testing.T) {
+	fmt.Println("Start")
+	t.Error("Error") // 程序继续执行
+	fmt.Println("End")
+}
+
+func TestFatalInCode(t *testing.T) {
+	fmt.Println("Start")
+	t.Fatal("Error") // 程序会中断 不会输出End
+	fmt.Println("End")
+}
+
+// 使用断言Assert测试
+func TestSquareWithAssert(t *testing.T) {
+	// 输入值
+	inputs := [...]int{1, 2, 3}
+	// 期待值
+	expected := [...]int{1, 4, 9}
+	for i := 0; i < len(inputs); i++ {
+		ret := Square(inputs[i])
+		assert.Equal(t, expected[i], ret)
+	}
+}
diff --git a/src/c2_const_test/constant_test.go b/src/c2_const_test/constant_test.go
new file mode 100644
index 0000000..6570e67
--- /dev/null
+++ b/src/c2_const_test/constant_test.go
@@ -0,0 +1,36 @@
+package constant_test
+
+import "testing"
+
+// 声明常量
+const (
+	// 连续常量写法 借助 iota
+	Monday = iota + 1
+	Tuesday
+	Wednesday
+)
+
+const (
+	// 位运算
+	Readable = 1 << iota
+	Writeable
+	Executable
+)
+
+const (
+	Cat = 1
+	Dog = 2
+	Pig = 3
+)
+
+func TestConstant(t *testing.T) {
+	t.Log(Monday, Tuesday)
+}
+
+func TestConstant1(t *testing.T) {
+	a := 1
+	t.Log(a&Readable, a&Writeable, a&Executable)
+
+	t.Log(a&Readable == Readable, a&Writeable == Writeable, a&Executable == Executable)
+
+}
diff --git a/src/c2_const_test/fib_test/fib_test.go b/src/c2_const_test/fib_test/fib_test.go
new file mode 100644
index 0000000..6127775
--- /dev/null
+++ b/src/c2_const_test/fib_test/fib_test.go
@@ -0,0 +1,47 @@
+package fib
+
+import (
+	"testing"
+)
+
+func TestFibList(t *testing.T) {
+	// var a int = 1
+	// var b int = 1
+
+	// var (
+	// 	a int = 1
+	// 	b int = 1
+	// )
+
+	a := 1
+	b := 1
+	t.Log(a)
+	for i := 0; i < 5; i++ {
+		t.Log(b)
+		tmp := a
+		a = b
+		b = tmp + a
+	}
+}
+
+func TestExchange(t *testing.T) {
+	// 其他编程语言常见写法 借助中间变量tmp
+	a := 1
+	b := 2
+	tmp := a
+	a = b
+	b = tmp
+	t.Log(a, b)
+
+	// go 值替换
+	a, b = b, a
+	t.Log(a, b)
+}
+
+func TestDemo(t *testing.T) {
+	a := "123"
+	b := "321"
+	t.Log(&a, &b)
+	a, b = b, a
+	t.Log(&a, &b, a, b)
+}
diff --git a/src/c2_const_test/first_test.go b/src/c2_const_test/first_test.go
new file mode 100644
index 0000000..e9b01ee
--- /dev/null
+++ b/src/c2_const_test/first_test.go
@@ -0,0 +1,9 @@
+package constant_test
+
+import (
+	"testing"
+)
+
+func TestFirst(t *testing.T) {
+	t.Log("我的第一个go测试程序!")
+}
diff --git a/src/c3_type_test/type_test.go b/src/c3_type_test/type_test.go
new file mode 100644
index 0000000..31fac0d
--- /dev/null
+++ b/src/c3_type_test/type_test.go
@@ -0,0 +1,39 @@
+package tpye_test
+
+import (
+	"math"
+	"testing"
+)
+
+// 自定义类型
+type MyInt int64
+
+// 类型转换
+func TestImplicit(t *testing.T) {
+	var a int32 = 1
+	// 显示类型转换
+	var b = int64(a)
+	var c = MyInt(b)
+	t.Log(a, b, c)
+}
+
+// 指针
+func TestPoint(t *testing.T) {
+	a := 1
+	aPtr := &a
+	t.Log(a, aPtr)
+	t.Logf("%T %T", a, aPtr)
+}
+
+func TestString(t *testing.T) {
+	// 不赋值默认空字符串
+	var s string
+	t.Log("*" + s + "*")
+	t.Log(len(s))
+	t.Log(s == "")
+}
+
+func TestMax(t *testing.T) {
+	t.Log(math.MaxFloat64)
+	t.Log(math.MaxInt64)
+}
diff --git a/src/c4_operator_test/operator_test.go b/src/c4_operator_test/operator_test.go
new file mode 100644
index 0000000..cd4bd82
--- /dev/null
+++ b/src/c4_operator_test/operator_test.go
@@ -0,0 +1,30 @@
+package operator_test
+
+import "testing"
+
+// 数组比较
+func TestCompareArray(t *testing.T) {
+	a := [...]int{1, 2, 3, 4}
+	b := [...]int{1, 2, 3, 5}
+	d := [...]int{1, 2, 3, 4}
+	t.Log(a == b)
+	//c := [...]int{1, 2, 3, 4, 5}
+	//t.Log(a == c)  //报错 长度不同不能比较
+	t.Log(a == d)
+
+}
+
+const (
+	// 位运算
+	Readable = 1 << iota
+	Writeable
+	Executable
+)
+
+func TestBitClear(t *testing.T) {
+	a := 7
+	a = a &^ Readable
+	a = a &^ Executable
+	t.Log(a&Readable, a&Writeable, a&Executable)
+	t.Log(a&Readable == Readable, a&Writeable == Writeable, a&Executable == Executable)
+}
diff --git a/src/c5_condition/condition_test.go b/src/c5_condition/condition_test.go
new file mode 100644
index 0000000..18b4dd3
--- /dev/null
+++ b/src/c5_condition/condition_test.go
@@ -0,0 +1,40 @@
+package condition_test
+
+import "testing"
+
+// if
+func TestIfMultiSec(t *testing.T) {
+	if a := 1 == 1.0; a {
+		t.Log("1 == 1")
+	} else {
+		t.Log("!=")
+	}
+}
+
+// switch
+func TestSwitchMultiCase(t *testing.T) {
+	for i := 0; i < 5; i++ {
+		switch i {
+		case 0, 2:
+			t.Log("偶数Even")
+		case 1, 3:
+			t.Log("基数Odd")
+		default:
+			t.Log("it is not 0-3")
+		}
+	}
+}
+
+// switch2
+func TestSwitchCaseCondition(t *testing.T) {
+	for i := 0; i < 5; i++ {
+		switch {
+		case i%2 == 0:
+			t.Log("偶数Even")
+		case i%2 == 1:
+			t.Log("基数Odd")
+		default:
+			t.Log("it is default case")
+		}
+	}
+}
diff --git a/src/c6_array_test/array_test.go b/src/c6_array_test/array_test.go
new file mode 100644
index 0000000..4685fae
--- /dev/null
+++ b/src/c6_array_test/array_test.go
@@ -0,0 +1,39 @@
+package array_test
+
+import "testing"
+
+// 数组声明
+func TestArrayInit(t *testing.T) {
+	var arr [3]int
+	arr1 := [4]int{1, 2, 3, 4}
+	arr3 := [...]int{1, 3, 4, 5}
+	arr1[1] = 5
+	t.Log(arr[1], arr[2])
+	t.Log(arr1, arr3)
+}
+
+// 数组遍历
+func TestArrayTravel(t *testing.T) {
+	arr3 := [...]int{1, 3, 4, 5}
+	for i := 0; i < len(arr3); i++ {
+		t.Log(arr3[i])
+	}
+
+	for idx, v := range arr3 {
+		t.Log(idx, v)
+	}
+
+	for _, v := range arr3 {
+		t.Log(v)
+	}
+}
+
+// 数组截断
+func TestArraySection(t *testing.T) {
+	arr3 := [...]int{1, 2, 3, 4, 5}
+	// 截取 arr[开始索引(包含), 结束索引(不包含)]
+	arr3_sec := arr3[1:4]
+	t.Log(arr3_sec) //2.3.4
+	t.Log(arr3[1:]) //2,3,4,5
+	t.Log(arr3[:3]) //1,2,3
+}
diff --git a/src/c6_loop/loop_test.go b/src/c6_loop/loop_test.go
new file mode 100644
index 0000000..a8ab636
--- /dev/null
+++ b/src/c6_loop/loop_test.go
@@ -0,0 +1,12 @@
+package loop_test
+
+import "testing"
+
+// for循环
+func TestWhileLoop(t *testing.T) {
+	n := 0
+	for n < 5 {
+		t.Log(n)
+		n++
+	}
+}
diff --git a/src/c6_slice_test/slice_test.go b/src/c6_slice_test/slice_test.go
new file mode 100644
index 0000000..33808cf
--- /dev/null
+++ b/src/c6_slice_test/slice_test.go
@@ -0,0 +1,51 @@
+package slice_test
+
+import "testing"
+
+// 切片定义
+func TestSlienceInit(t *testing.T) {
+	var s0 []int
+	t.Log(len(s0), cap(s0))
+	s0 = append(s0, 1)
+	t.Log(len(s0), cap(s0))
+
+	s1 := []int{1, 2, 3, 4}
+	t.Log(len(s1), cap(s1))
+
+	s2 := make([]int, 3, 5)
+	t.Log(len(s2), cap(s2))
+	t.Log(s2[0], s2[1], s2[2])
+	s2 = append(s2, 4)
+	t.Log(len(s2), cap(s2))
+	t.Log(s2[0], s2[1], s2[2], s2[3])
+}
+
+// 切片增长演示
+func TestSliceGrowing(t *testing.T) {
+	s := []int{}
+	for i := 0; i < 10; i++ {
+		s = append(s, i)
+		t.Log(len(s), cap(s))
+	}
+}
+
+// 切片的共享内存 演示
+func TestSliceShareMemory(t *testing.T) {
+	letter := []string{"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "L"}
+	letter2 := letter[3:6]
+	t.Log(letter2, len(letter2), cap(letter2))
+	l3 := letter[5:8]
+	t.Log(l3, len(l3), cap(l3))
+	l3[0] = "U"
+	t.Log(letter2)
+	t.Log(letter)
+}
+
+// 切片不能比较
+func TestSliceCompare(t *testing.T) {
+	// a := []int{1, 2, 3, 4}
+	// b := []int{1, 2, 3, 4}
+	// if a == b {
+	// 	t.Log("equals")
+	// }
+}
diff --git a/src/c7_map_test/map_test.go b/src/c7_map_test/map_test.go
new file mode 100644
index 0000000..0b6e90e
--- /dev/null
+++ b/src/c7_map_test/map_test.go
@@ -0,0 +1,50 @@
+package map_test
+
+import (
+	"testing"
+)
+
+// map的声明
+func TestMapInit(t *testing.T) {
+	m1 := map[string]int{"a": 1, "b": 2, "c": 3}
+	t.Log(m1["b"])
+	t.Logf("len m1=%d", len(m1))
+
+	m2 := map[string]int{}
+	m2["d"] = 4
+	t.Logf("len m2=%d", len(m2))
+	m3 := make(map[string]int, 10)
+	t.Logf("len m3=%d", len(m3))
+}
+
+// map判断键key是否存在
+func TestAccessNotExistingKey(t *testing.T) {
+	m1 := map[int]int{}
+	// 不存在会默认为0 而不是nil
+	t.Log(m1[1])
+	m1[2] = 0
+	t.Log(m1[2])
+
+	if v, ok := m1[3]; ok {
+		t.Logf("Key 3 value is %d", v)
+	} else {
+		t.Log("Key 3 is not exist")
+	}
+
+	// 赋值后
+	m1[3] = 0
+	if v, ok := m1[3]; ok {
+		t.Logf("Key 3 value is %d", v)
+	} else {
+		t.Log("Key 3 is not exist")
+	}
+
+}
+
+// 遍历Map
+func TestTravelMap(t *testing.T) {
+	m1 := map[string]int{"a": 1, "b": 2, "c": 3}
+	for k, v := range m1 {
+		t.Logf("Key: %s, Value: %d", k, v)
+	}
+}
diff --git a/src/c8_map_ext/map_ext_test.go b/src/c8_map_ext/map_ext_test.go
new file mode 100644
index 0000000..86fa062
--- /dev/null
+++ b/src/c8_map_ext/map_ext_test.go
@@ -0,0 +1,48 @@
+package map_ext
+
+import (
+	"fmt"
+	"testing"
+)
+
+// 值为方法的map
+func TestMapWithFunValue(t *testing.T) {
+	m := map[int]func(op int) int{}
+	m[1] = func(op int) int { return op }
+	m[2] = func(op int) int { return op * op }
+	m[3] = func(op int) int { return op + op + op }
+	t.Log(m[1](2), m[2](2), m[3](2))
+}
+
+// Map实现Set操作
+func TestMapForSet(t *testing.T) {
+	mySet := map[int]bool{}
+
+	// 添加元素
+	mySet[1] = true
+	mySet[2] = false
+	t.Logf("set len=%d", len(mySet))
+
+	// 判断元素是否存在
+	n := 3
+	if mySet[n] {
+		t.Logf("%d is exist", n)
+	} else {
+		t.Logf("%d is not exist", n)
+	}
+
+	//删除元素
+	delete(mySet, 1)
+	ValueIsExit(mySet, 1)
+
+}
+
+func ValueIsExit(s map[int]bool, v int) bool {
+	if s[v] {
+		fmt.Printf("%d is exist", v)
+		return true
+	} else {
+		fmt.Printf("%d is not exist", v)
+		return false
+	}
+}
diff --git a/src/c9_string/string_func_test.go b/src/c9_string/string_func_test.go
new file mode 100644
index 0000000..3e4fdd4
--- /dev/null
+++ b/src/c9_string/string_func_test.go
@@ -0,0 +1,31 @@
+package string_test
+
+import (
+	"strconv"
+	"strings"
+	"testing"
+)
+
+func TestStringFn(t *testing.T) {
+	s := "A,B,C"
+	// 切割
+	parts := strings.Split(s, ",")
+	for _, v := range parts {
+		t.Log(v)
+	}
+
+	// 连接
+	t.Log(strings.Join(parts, "-"))
+}
+
+func TestStrConv(t *testing.T) {
+	// int to string
+	s := strconv.Itoa(10)
+	t.Log(s)
+
+	// string to int
+	if i, err := strconv.Atoi("10"); err == nil {
+		t.Log(10 + i)
+	}
+
+}
diff --git a/src/c9_string/string_test.go b/src/c9_string/string_test.go
new file mode 100644
index 0000000..f11e3ea
--- /dev/null
+++ b/src/c9_string/string_test.go
@@ -0,0 +1,29 @@
+package string_test
+
+import "testing"
+
+func TestString(t *testing.T) {
+	var s string
+	t.Log(s) //初始化值为空字符串 ""
+	s = "hello"
+	t.Log(len(s))
+
+	s = "\xE4\xB8\xA5" // 可以存储任何二进制数据
+	// s = "\xE4\xBA\xB5\xFF"
+	t.Log(s)
+
+	s = "中"
+	t.Log(len(s)) // 是byte数
+
+	c := []rune(s)
+	t.Log(len(c))
+	t.Logf("中 unicode %x", c[0])
+	t.Logf("中 UTF8 %x", s)
+}
+
+func TestStringToRune(t *testing.T) {
+	s := "中华人民共和国"
+	for _, c := range s {
+		t.Logf("%[1]c %[1]d, %[1]x", c)
+	}
+}