From d043ee5b33d6de7e546e028c364811bf536dd2f9 Mon Sep 17 00:00:00 2001
From: acevest <zhaoyanbai@126.com>
Date: Tue, 20 Jan 2015 16:22:13 +0800
Subject: [PATCH] ...

---
 learn/go/error.go       | 28 +++++++++++++++++++
 learn/lex/a.l           |  6 ++--
 learn/markdown/index.md | 61 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 92 insertions(+), 3 deletions(-)
 create mode 100644 learn/go/error.go
 create mode 100644 learn/markdown/index.md

diff --git a/learn/go/error.go b/learn/go/error.go
new file mode 100644
index 0000000..905bd59
--- /dev/null
+++ b/learn/go/error.go
@@ -0,0 +1,28 @@
+package main
+
+import (
+	"fmt"
+)
+
+type ErrNegativeSqrt float64
+
+func (e ErrNegativeSqrt) Error() string {
+	return fmt.Sprintf("cannot Sqrt negative number: %g\n", float64(e))
+}
+
+func Sqrt(x float64) (float64, error) {
+	z := 1.0
+	if x >= 0 {
+		for i := 0; i < 10; i++ {
+			z = z - (z*z-x)/(2*z)
+		}
+	} else {
+		return 0, ErrNegativeSqrt(x)
+	}
+	return z, nil
+}
+
+func main() {
+	fmt.Println(Sqrt(2))
+	fmt.Println(Sqrt(-2))
+}
diff --git a/learn/lex/a.l b/learn/lex/a.l
index 1ef8160..265702d 100644
--- a/learn/lex/a.l
+++ b/learn/lex/a.l
@@ -30,9 +30,9 @@ could |
 has |
 have |
 had |
-go		{ printf("%s: is a verb\n", yytext); }
-[a-zA-Z]+	{ printf("%s: is not a verb\n", yytext); }
-[0-9]+		{ printf("%s: is a num\n", yytext); }
+go		{ printf("%s: is a verb", yytext); }
+[a-zA-Z]+	{ printf("%s: is not a verb", yytext); }
+[0-9]+		{ printf("%s: is a num", yytext); }
 .|\n		{ ECHO; /* 通常的默认状态 */ }
 
 %%
diff --git a/learn/markdown/index.md b/learn/markdown/index.md
new file mode 100644
index 0000000..8bd5b3e
--- /dev/null
+++ b/learn/markdown/index.md
@@ -0,0 +1,61 @@
+#这是H1#
+##这是H2##
+###这是H3###
+#####这是H4####
+######这是H5#####
+######这是H6######
+
+vxcvzdfdsf  
+fsadfasdf  
+sfasdf
+
+> q adfads sdfads
+> fa
+> afdsfadfasdfasdfsadf
+> sfa
+> sdfasdf
+> fs fsadf   
+> dsafsd  
+> fsdfa  
+> dsf  
+> sadfasd  
+
+
+这是一个*强调*示例，这是另一个 _强调_ 示例  
+这是一个**加重强调**示例 或 __加重强调__
+这是一个***特别强调***示例 或 ___特别强调___
+
+
+这是个命令示例`echo "Hello World"` 输出什么?  
+
+
+
+```
+#include <stdio.h>
+int main() {
+	printf("Hello, World\n");
+	return 0;
+}
+```
+
+以下是水平分割线
+* * *  
+或
+***
+或
+*****
+或
+- - -  
+
+链接
+[Hello](http://www.qq.com)
+or
+[Tag][Link]
+[Link]: http://www.qq.com "sfasd"
+
+
+
+
+
+
+
-- 
2.44.0