重学Go语言之运算符与控制结构详解

var i,j = 1,2
n := i + j

var str1 string = "hello"
var str2 string = "world"
str := str1 + str2 //使用+号拼接字符串

i := 3.2 % 2 //报错，只能对整数求余

var n int = 1
n++ 
++n //错误，自增只能加了操作数后面，自减也是同样的

if 2 == (1 + 1) {
	fmt.Println("相等")
}

fmt.Println(2 & 1) // 00000010 & 00000001，可以看出，没有哪个位置两个操作都为1，因此结果为：00000000
fmt.Println(2 | 1) // 00000010 & 00000001，结果为00000011，也就是3
fmt.Println(2 ^ 1) // 00000010 & 00000001，结果为00000011，也就是3

fmt.Println(1 << 1) //00000001 => 00000010 
fmt.Println(2 >> 1) //00000010 => 00000001

fmt.Println(23 &^ 5) 00010111 &^ 00000101 => 00010010 

if boolean expression {
	// do something	
}

if 2 < 10 {
	fmt.Println("ok")
}

if initialization;boolean expression{
	// do something	
}

if i = 10;i < 100 {
	fmt.Println("ok")
}

if boolean expression{
	// do something	
}else{
	// do something	
}

if i = 11;i < 11{
	fmt.Println("ok")
}else{
	fmt.Println("bad")
}

if boolean expression1 {
	// do something	
} else if boolean expression2 {
	// do something else	
} else if boolean expression3 {
	// do something else	
}else {
	// catch-all or default
}

for condition {
	//do something
}

x := 1
for x < 20{
	fmt.Println(x)
	x++
}

for {
	//do something
}

for init statement;condition;post statement{
	//do something
}

for i := 0; i< 10 ;i++ {
	fmt.Println(i)
}

for k,v := range array {
	//do something
}

var a [10]int = [10]int{1,2,3,4,5,6,7,8,9,10}

for index,value := range a {
	fmt.Println(index,value)
}

for i := 0; i < 10; i++ {
	if i == 5 {
		break
	}
	fmt.Println(i)
}

for i := 0;i<10;i++{
	if i == 5 {
		continue
	}
	fmt.Println(i)
}

switch var1 {
	case val1:
		...
	case val2:
		...
	default:
		...
}

var x = 8
switch x {
	case 8 :
		fmt.Println("8")
	case 9 :
	  fmt.Println("9")
	case 10 :
	  fmt.Println("10")
	default :
		fmt.Println("not found")
}

var x = 8
switch x {
	case 8 :
		fmt.Println("8")
		fallthrough
	case 9 :
	  fmt.Println("9")
	  fallthrough
	case 10 :
	  fmt.Println("10")
	default :
		fmt.Println("not found")
}

switch {
	case condition1:
		...
	case condition2:
		...
	default:
		...
}

x := 10
switch {
	case x >= 10:
		fmt.Println("10")
	case x > 11:
		fmt.Println("11")
	default:
		fmt.Println("not found")
}

switch initialization {
	case condition1:
		...
	case condition2:
		...
	default:
		...
}

switch x := 10; {
	case x >= 10:
		fmt.Println("10")
	case x > 11:
		fmt.Println("11")
	default:
		fmt.Println("not found")
}