精校：5.4

eBook/05.4.md

@@ -10,9 +10,9 @@
 
 	for 初始化语句; 条件语句; 修饰语句 {}
 
-Listing 5.6 [for1.go](examples/chapter_5/for1.go)：
+示例 5.6 [for1.go](examples/chapter_5/for1.go)：
 
-```
+```go
 package main
 
 import "fmt"
@@ -26,13 +26,11 @@ func main() {
 
 输出：
 
-```
-This is the 0 iteration
-This is the 1 iteration
-This is the 2 iteration
-This is the 3 iteration
-This is the 4 iteration
-```
+	This is the 0 iteration
+	This is the 1 iteration
+	This is the 2 iteration
+	This is the 3 iteration
+	This is the 4 iteration
 
 由花括号括起来的代码块会被重复执行已知次数，该次数是根据计数器（此例为 i）决定的。循环开始前，会执行且仅会执行一次初始化语句 `i := 0;`；这比在循环之前声明更为简短。紧接着的是条件语句 `i < 5;`，在每次循环开始前都会进行判断，一旦判断结果为 false，则退出循环体。最后一部分为修饰语句 `i++`，一般用于增加或减少计数器。
 
@@ -44,13 +42,15 @@ This is the 4 iteration
 
 您还可以在循环中同时使用多个计数器：
 
-	for i, j := 0, N; i < j; i, j = i+1, j-1 {}
+```go
+for i, j := 0, N; i < j; i, j = i+1, j-1 {}
+```
 
 这得益于 Go 语言具有的平行赋值的特性（可以查看第 7 章 string_reverse.go 中反转数组的示例）。
 
 您可以将两个 for 循环嵌套起来：
 
-```
+```go
 for i:=0; i<5; i++ {
 	for j:=0; j<10; j++ {
 		println(j)
@@ -60,9 +60,9 @@ for i:=0; i<5; i++ {
 
 如果您使用 for 循环迭代一个 Unicode 编码的字符串，会发生什么？
 
-Listing 5.7 [for_string.go](examples/chapter_5/for_string.go)：
+示例 5.7 [for_string.go](examples/chapter_5/for_string.go)：
 
-```
+```go
 package main
 
 import "fmt"
@@ -83,46 +83,44 @@ func main() {
 
 输出：
 
-```
-The length of str is: 27
-Character on position 0 is: G 
-Character on position 1 is: o 
-Character on position 2 is:   
-Character on position 3 is: i 
-Character on position 4 is: s 
-Character on position 5 is:   
-Character on position 6 is: a 
-Character on position 7 is:   
-Character on position 8 is: b 
-Character on position 9 is: e 
-Character on position 10 is: a 
-Character on position 11 is: u 
-Character on position 12 is: t 
-Character on position 13 is: i 
-Character on position 14 is: f 
-Character on position 15 is: u 
-Character on position 16 is: l 
-Character on position 17 is:   
-Character on position 18 is: l 
-Character on position 19 is: a 
-Character on position 20 is: n 
-Character on position 21 is: g 
-Character on position 22 is: u 
-Character on position 23 is: a 
-Character on position 24 is: g 
-Character on position 25 is: e 
-Character on position 26 is: ! 
-The length of str2 is: 9
-Character on position 0 is: æ 
-Character on position 1 is: — 
-Character on position 2 is: ¥ 
-Character on position 3 is: æ 
-Character on position 4 is: œ 
-Character on position 5 is: ¬ 
-Character on position 6 is: è 
-Character on position 7 is: ª 
-Character on position 8 is: ž 
-```
+	The length of str is: 27
+	Character on position 0 is: G 
+	Character on position 1 is: o 
+	Character on position 2 is:   
+	Character on position 3 is: i 
+	Character on position 4 is: s 
+	Character on position 5 is:   
+	Character on position 6 is: a 
+	Character on position 7 is:   
+	Character on position 8 is: b 
+	Character on position 9 is: e 
+	Character on position 10 is: a 
+	Character on position 11 is: u 
+	Character on position 12 is: t 
+	Character on position 13 is: i 
+	Character on position 14 is: f 
+	Character on position 15 is: u 
+	Character on position 16 is: l 
+	Character on position 17 is:   
+	Character on position 18 is: l 
+	Character on position 19 is: a 
+	Character on position 20 is: n 
+	Character on position 21 is: g 
+	Character on position 22 is: u 
+	Character on position 23 is: a 
+	Character on position 24 is: g 
+	Character on position 25 is: e 
+	Character on position 26 is: ! 
+	The length of str2 is: 9
+	Character on position 0 is: æ 
+	Character on position 1 is: — 
+	Character on position 2 is: ¥ 
+	Character on position 3 is: æ 
+	Character on position 4 is: œ 
+	Character on position 5 is: ¬ 
+	Character on position 6 is: è 
+	Character on position 7 is: ª 
+	Character on position 8 is: ž 
 
 如果我们打印 str 和 str2 的长度，会分别得到 27 和 9。
 
@@ -139,14 +137,12 @@ Character on position 8 is: ž
 
 创建一个程序，要求能够打印类似下面的结果（直到每行 25 个字符时为止）：
 
-```
-G
-GG
-GGG
-GGGG
-GGGGG
-GGGGGG
-```
+	G
+	GG
+	GGG
+	GGGG
+	GGGGG
+	GGGGGG
 
 1. 使用 2 层嵌套 for 循环。
 2. 使用一层 for 循环以及字符串截断。
@@ -171,7 +167,7 @@ for 结构的第二种形式是没有头部的条件判断迭代（类似其它
 
 Listing 5.8 [for2.go](examples/chapter_5/for2.go)：
 
-```
+```go
 package main
 
 import "fmt"
@@ -188,14 +184,12 @@ func main() {
 
 输出：
 
-```
-The variable i is now: 4
-The variable i is now: 3
-The variable i is now: 2
-The variable i is now: 1
-The variable i is now: 0
-The variable i is now: -1
-```
+	The variable i is now: 4
+	The variable i is now: 3
+	The variable i is now: 2
+	The variable i is now: 1
+	The variable i is now: 0
+	The variable i is now: -1
 
 ## 5.4.3 无限循环
 
@@ -209,7 +203,7 @@ The variable i is now: -1
 
 无限循环的经典应用是服务器，用于不断等待和接受新的请求。
 
-```
+```go
 for t, err = p.Token(); err == nil; t, err = p.Token() {
 	...
 }
@@ -221,7 +215,7 @@ for t, err = p.Token(); err == nil; t, err = p.Token() {
 
 要注意的是，`val` 始终为集合中对应索引的值拷贝，因此它一般只具有只读性质，对它所做的任何修改都不会影响到集合中原有的值（**译者注：如果 `val` 为指针，则会产生指针的拷贝，依旧可以修改集合中的原值**）。一个字符串是 Unicode 编码的字符（或称之为 `rune`）集合，因此您也可以用它迭代字符串：
 
-```
+```go
 for pos, char := range str {
 ...
 }
@@ -229,9 +223,9 @@ for pos, char := range str {
 
 每个 rune 字符和索引在 for-range 循环中是一一对应的。它能够自动根据 UTF-8 规则识别 Unicode 编码的字符。
 
-Listing 5.9 [range_string.go](examples/chapter_5/range_string.go)：
+示例 5.9 [range_string.go](examples/chapter_5/range_string.go)：
 
-```
+```go
 package main
 
 import "fmt"
@@ -323,7 +317,7 @@ index int(rune) rune    char bytes
 
 **练习 5.9** 以下程序的输出结果是什么？
 
-```
+```go
 for i := 0; i < 5; i++ {
 	var v int
 	fmt.Printf("%d ", v)
@@ -335,7 +329,7 @@ for i := 0; i < 5; i++ {
 
 1.
 
-```
+```go
 for i := 0; ; i++ {
 	fmt.Println("Value of i is now:", i)
 }
@@ -343,7 +337,7 @@ for i := 0; ; i++ {
 
 2.
 
-```
+```go
 for i := 0; i < 3; {
 	fmt.Println("Value of i:", i)
 }
@@ -351,7 +345,7 @@ for i := 0; i < 3; {
 
 3.
 
-```
+```go
 s := ""
 for ; s != "aaaaa"; {
 	fmt.Println("Value of s:", s)
@@ -361,7 +355,7 @@ for ; s != "aaaaa"; {
 
 4.
 
-```
+```go
 for i, j, s := 0, 5, "a"; i < 3 && j < 100 && s != "aaaaa"; i, j,
 	s = i+1, j+1, s + "a" {
 	fmt.Println("Value of i, j, s:", i, j, s)