swift的基本语法

最近看视频学习swift，以下是观看极客学院视频后经自己整理后写出的代码

//1.打印

println("Hello, Swift!");

//2.变量和常量
var v1 =
1;
var v2 =
2;

//常量一经定义不可改变
let v3 =
v1 + v2;

//v3 = 8

println("v1 =
\(v1) v2=\(v2) v3 =
\(v3) ")

//3.数据类型

var str = "Hello "

var s:String =
"world"
var i1:Int =
10;
var word:String =
"Swift"

println(word)

//4.字符串的连接

var s1 = "Hello "
var i2 =
900;

s1 = s1 +
"Swift " + "Next"

println(s1)
s1 =
"\(s1) +
\(1000) +\(i2)"

println(s1)

//5.语言数组

var arr = ["Hello","Swift",100,200.0,5.6]
var arr1 = []
var arr2 = [String]()

println(arr)

//6.字典

var dict = ["name":"xutao","sex":"male"]

dict["profession"]="iOS engineer"

println(dict)

println(dict["sex"])

//7.循环
var arr3 = [String]()

for index
in 1...100{

arr3.append("Item
\(index)")

}

println(arr3)

//for value in arr3{

//

//println(value)

//

//}

var i =
0

while i<arr3.count{

println(arr3[i]);

i++;

}

var dict1=["name":"xutao","age":"24","sex":"male"]
for (key,value)
in dict1{

println("\(key),\(value)")

}

//8.语言流程控制

for
index in
0...100{

if(index%2==0){

println(index)
}

}

//可选变量
var myName :String? =
"xutao"

//如果myname==nil;就不会执行判断语句

myName = nil;
if
let name = myName{

println("yes");

}else{

println("nil")
}

//9.语言函数
func sayHello(name:String){

println("Hello,Swift
\(name)")
}

sayHello("I am learning it.")

//多个返回值
func moreReturnValue()->(Int,String){

return(10,"baby")
}

let(a,b)=moreReturnValue();

println(b);

var fun =
sayHello;

fun("just do it")

//10.面向对象

//建立一个HI类

class Hi{

//建立一个方法

func print(){

println("swift first")

}
}
var hi =
Hi()

hi.print();

//继承
class inherit:Hi{

//重写方法

// override func print() {

// println("swift first overwrite")

// }

//构造方法

var _name:String

init(name:String) {

self._name=name;
}

override func print() {

println("swift first
\(self._name)")
}

}
var hiInherit =
inherit(name: "Init");

hiInherit.print();