//: Playground - noun:效果图一二对应代码如下

import UIKit

var str = "Hello,playground"

//操作符
// - ++ -- 一元操作符
// +-*/ 二元操作符
// a?b:c 三元操作符

//子增减可以是整数活浮点数
var a = 1.5
var b = a++
var c = ++a
println("a: \(a) b: \(b) c: \(c)")
a+=2//a=a+2
a-=2//a=a-2


//三元操作符
var d = (a < b ? a : b)

//如果a<b 的话 d = a 否则 d = b

//区间操作符
let char_arr = ["a","b","c","d"]

//枚举数组
for i in 0..<char_arr.count
{
    println("第\(i)个字符为\(char_arr[i])")
}


//逻辑操作符
let t = true
let f = false
if t&&f
{
    println("\(t)&&\(f)")
}
else
{
    println("\(t)&&\(f)")
}

if t||f
{
    println("\(t)&&\(f)")
}
else
{
    println("\(t)&&\(f)")
}

var t_f = !f

if t_f && (t||f)
{
    println("\(t_f) \(t) \(f)")
}