diff --git a/src/study/day6/map.go b/src/study/day6/map.go
index c08f4d9..e89dd29 100644
--- a/src/study/day6/map.go
+++ b/src/study/day6/map.go
@@ -38,7 +38,7 @@ func main() {
 	map1["bob"] = map1["bob"] + 1
 	fmt.Println(map1)
 	fmt.Println(map1["qaq"]) // 0
-
+	print("ll")
 	// x += y, x++等简短赋值语句在map上也适用
 	map1["bob"] += 1
 	fmt.Println(map1["bob"]) // 2
diff --git a/src/study/day6/treesort.go b/src/study/day6/treesort.go
index 6e7be5e..8241114 100644
--- a/src/study/day6/treesort.go
+++ b/src/study/day6/treesort.go
@@ -32,7 +32,6 @@ func add(t *tree, value int) *tree {
 		t.value = value
 		return t
 	}
-
 	if value < t.value {
 		t.left = add(t.left, value)
 		//fmt.Println("left", t.value)
@@ -43,7 +42,6 @@ func add(t *tree, value int) *tree {
 	//fmt.Println(value)
 	return t
 }
-
 func main() {
 	var nums []int = []int{4, 5, 43, 323, 45, 98, 4, 5, 7, 8, 1, 3, 2, 565}
 	fmt.Println(nums)
diff --git a/src/study/day7Function/ErrorProcess.go b/src/study/day7Function/ErrorProcess.go
new file mode 100644
index 0000000..ad1d2a6
--- /dev/null
+++ b/src/study/day7Function/ErrorProcess.go
@@ -0,0 +1,97 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"os"
+)
+
+type Myerror struct {
+	error
+}
+
+func (Myerror) Error() string {
+	//TODO implement me
+	fmt.Println("俺真的错了！")
+	panic("implement me")
+}
+
+const (
+	Error = iota + 31
+	Info
+	Warn
+	Debug
+	Panic
+)
+
+func ProcessErrStr(c int, s error) string {
+	return fmt.Sprintf("\x1b[0;%dm%v\x1b[0m", c, s)
+}
+
+func main() {
+	// errors.New方法可以字符串创建一个error
+	// 类似于fmt.Errorf方法
+	CheckStr := func(s string) error {
+		if s == "" {
+			return errors.New("the str must be not empty")
+		}
+		return nil
+	}
+	//fmt.Println(CheckStr(""))
+	//fmt.Println(CheckStr("abc"))
+
+	// 当错误发生后，一般有三种方式来处理错误
+
+	// 第一种，使用fmt.Fprintf方法将错误打印到stderr， 并终止程序
+	if err := CheckStr(""); err != nil {
+		if _, err := fmt.Fprintf(os.Stderr, "1. %v\n", ProcessErrStr(Panic, err)); err != nil {
+			os.Exit(1)
+		}
+	}
+
+	// 第二种，使用log.Fatalf,这种方式等于是上面的那种方法，都是输出致命的错误后，退出程序
+	// 调用log.Fatalf可以更简洁的代码达到与上文相同的效果。log中的所有函数，都默认会在错误信息之前输出时间信息。
+	// 等价于{Printf(v...); os.Exit(1)}
+	//if err := CheckStr(""); err != nil {
+	//	log.Fatalf("2. %v\n", ProcessErrStr(Error, err))
+	//}
+	// 我们也可以屏蔽掉log的日期输出
+	/* see https://www.flysnow.org/2017/05/06/go-in-action-go-log */
+	log.SetPrefix(ProcessErrStr(Error, errors.New("ERR: ")))
+	log.SetFlags(log.Ldate | log.Ltime | log.LUTC | log.Lshortfile)
+	//if err := CheckStr(""); err != nil {
+	//	log.Fatalf("2.1. %v\n", ProcessErrStr(Error, err))
+	//}
+
+	// 最后我们也可以直接忽略到错误的发生，不做处理, 仅做stdout输出。
+	if err := CheckStr(""); err != nil {
+		if _, err := fmt.Fprintf(os.Stdout, "3. %v\n", ProcessErrStr(Panic, err)); err != nil {
+			log.Fatalln("标准输出失败")
+		}
+	}
+
+	// error错误有时并不是代表致命错误，或者程序运行错误，而是根据错误类型，做出不同的相应
+	// 其中EOF错误就是一种，调用者会重复的读取固定大小的数据直到文件结束。
+	// 这会导致调用者必须分别处理由文件结束引起的各种错误。
+	readFile := func() error {
+		in := bufio.NewReader(os.Stdin)
+		for {
+			r, _, err := in.ReadRune()
+			if err == io.EOF {
+				break // finished reading
+			}
+			if err != nil {
+				return fmt.Errorf("read failed:%v", err)
+			}
+			// ...use r…
+			fmt.Println(r)
+		}
+		return nil
+	}
+	if err := readFile(); err != nil {
+		log.Fatalln("EOF!")
+	}
+}
diff --git a/src/study/day7Function/MultiReturn.go b/src/study/day7Function/MultiReturn.go
new file mode 100644
index 0000000..410547a
--- /dev/null
+++ b/src/study/day7Function/MultiReturn.go
@@ -0,0 +1,65 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"time"
+)
+
+// go中 函数可以拥有多个返回值，
+
+func BothAdd(a, b int, action func(nun int) int) (int, int, error) {
+	if a == 0 || b == 0 {
+		return 0, 0, errors.New("the num must not be 0")
+	}
+	return action(a), action(b), nil
+}
+func Add(num int) int {
+	num++
+	return num
+
+}
+func PointAdd(num *int) {
+	*num++
+}
+
+func Concat2(a string, bOptional ...int) string {
+	b := 5
+	if len(bOptional) > 0 {
+		b = bOptional[0]
+	}
+
+	return fmt.Sprintf("%s%d", a, b)
+}
+func swap(a, b int) (int, int) {
+	a, b = b, a
+	return a, b
+
+}
+
+func Sum[T int | float64](a, b T) T {
+	return a + b
+}
+
+func APprint(s chan string) {
+	for i := 0; i < 10; i++ {
+		fmt.Println(<-s)
+		time.Sleep(time.Second)
+	}
+}
+func main() {
+	str := make(chan string, 5)
+	go APprint(str)
+	go APprint(str)
+	for true {
+		str <- "aaa"
+		str <- "\\CCC"
+	}
+	time.Sleep(time.Second * 20)
+	//fmt.Println(Sum[int](1, 2))
+	//fmt.Println(Sum(1.23, 2.3))
+	//number := 233
+	//PointAdd(&number)
+	//fmt.Println(number)
+
+}
diff --git a/src/study/day7Function/Recursive.go b/src/study/day7Function/Recursive.go
index 2072ecb..323aa70 100644
--- a/src/study/day7Function/Recursive.go
+++ b/src/study/day7Function/Recursive.go
@@ -18,14 +18,14 @@ func main() {
 		os.Exit(1)
 	}
 	//fmt.Println(doc.NextSibling.Data)
-	for _, link := range visit(nil, doc.FirstChild) {
+	for _, link := range Visit(nil, doc.FirstChild) {
 		fmt.Println(link)
 	}
 	//outline(nil, doc)
 }
 
 // visit appends to links each link found in n and returns the result.
-func visit(links []string, n *html.Node) []string {
+func Visit(links []string, n *html.Node) []string {
 	if n == nil {
 		return links
 	}
@@ -43,8 +43,8 @@ func visit(links []string, n *html.Node) []string {
 	//if n != nil {
 	//	links = visit(links, n.NextSibling)
 	//}
-	links = visit(links, n.FirstChild)
-	links = visit(links, n.NextSibling)
+	links = Visit(links, n.FirstChild)
+	links = Visit(links, n.NextSibling)
 	return links
 }
 func outline(stack []string, n *html.Node) []string {