Golang 流程控制

2018-12-31 13:12:02 Albin Wong 1483

流程控制，条件语句，选择语句，跳转语句

### 流程控制
#### 条件语句 if...else...else if
```go
func example(x int) int { 
	if x == 0 {
		return 5 
	} else {
		return x 
	}
}
```
- 条件语句不需要使用括号将条件包含起来();
- 无论语句体内有几条语句，花括号{}都是必须存在的;
- 左花括号{必须与if或者else处于同一行;
- 在if之后，条件语句之前，可以添加变量初始化语句，使用;间隔;
- 在有返回值的函数中，不允许将“最终的”return语句包含在if...else...结构中

#### 选择语句 switch.case.select
**fallthrough** 只有在case中明确添加fallthrough关键字，才会继续执行紧跟的下一个case
```go
switch i { 
	case 0:
		fmt.Printf("0") 
	case 1:
		fmt.Printf("1") 
	case 2:
		fallthrough
	case 3:
		fmt.Printf("3") 
	case 4, 5, 6:
		if(i == 4) {
			fmt.Printf("4")
		} else {
			fmt.Printf("5 or 6")
		}
		// fmt.Printf("4, 5, 6") 
	default:
        fmt.Printf("Default")
}
```
#### 循环语句 for range
```go
// case one
sum := 0
for i := 0; i < 10; i++ {
	sum += i
	fmt.Println(sum)
}

// case two
sum := 0
i := 0
for {
    sum += i
    fmt.Println(sum)
    i++
    if i > 10 {
        break
	}
}

// case three
a := []int{1,2,3,4,5,6,7}
for i,j := 0,len(a) - 1; i < j; i,j = i + 1, j -1 {
	a[i], a[j] = a[j], a[i]
}
fmt.Println(a)

// 4. for循环同样支持continue和break来控制循环，但是它提供了一个更高级的break，可以选择中断哪一个循环
for j := 0; j < 5; j++ {
	for i :=0; i <10; i++ {
	    if i > 5 {
			continue
		}
	 	fmt.Println(i)
 	}
}
```

#### 跳转语句 goto
```go
i := 0
HERE:
	fmt.Println(i)
	i++
if i < 10 {
	goto HERE
}
fmt.Println("test")
```

(3) Comments

John Doe- Reply

February 26, 2013 at 1:18 pm
- saqib sarwar- Reply
  
  February 26, 2013 at 1:20 pm
  
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John Doe- Reply

February 26, 2013 at 1:27 pm

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Golang 流程控制

(3) Comments

John Doe- Reply

saqib sarwar- Reply

John Doe- Reply

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