1.基本运算符
1）一元运算符
- 自增自减运算符：++ --
- 正号负号运算符：+ -
- 逻辑非运算符：！
2）二元运算符
- 赋值运算符：a = b
- 算数运算符：+ = * /
- 求余运算符：%
- 符合赋值运算符： += -= *= /=
- 比较运算符： == != > < >= <=
- 空合运算符：?? a ?? b 相当于 a != nil ? a! : b
- 区间运算符：a...b a..<b
- 逻辑与或运算符：&& ||
3）三木运算符
- 问题？答案1：答案2
2.重载运算符
Struct Sword{
var length: Float
var weight:Float
var name :String
}
//重载运算符“+”
func +(left: Sword,right:Sword)->Sword{
return Sword(length : left.length + right.length,
weight : left.weight + right.weight,
name: “Big Sword”)
}
//重载前置运算符“-”
prefix func-(sword:Sword)->Sword{
return Sword(length: -sword.length,
weight: - sword.weight,
name: “Small Sword”)
}
//重载后置运算符“++”
postfix func++(inout Sword)->Sword{
var oldSword = Sword
sword.length += 1.0
sword.weight += 1.0
return oldSword
}
3.自定义运算符
infix operator +-* {associativity left precedence 140}
func +-*(left: Sword,right:Sword)->{
return Sword(length:left.length + right.length,
weight:left.weight + right.weight,
name:left.name + right.name)
}
第一段：operator infix/prefix/postfix自定义运算符{}
第二段：infix/prefix/postfix func (参数表) ->返回类型{}
4.示例代码：
println("Hello,World!")
let name = "sn"
let dog:Character = "a"
let cow:Character = "b"
//let dogCow = dog + cow
let contentHeight = 40
let hasHead = true
let roheight = contentHeight + (hasHead ? 50 : 20)
for index in 1...5
{
println(index)
}
let names = ["a","b","c","d"]
let countNumber = names.count
for index in 0..<countNumber
{
println(names[index])
}
for name in names
{
if name.hasPrefix("c"){
println("1")
}
}
for character in "asfedee"
{
println(character)
}
let heart = "\u{2665}"
println(heart)
let unusualMenagerie = "Koala
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