[Swift]变量与常量

Swift里变量用var,常量用let来定义

var a = 10
a = 20
var b = 100
let c = a + b

println(c) //120

c = 100 //error:Cannot assign to 'let' value 'c'

var a = 10

a = 20

var b = 100

let c = a + b

println(c) //120

c = 100 //error:Cannot assign to 'let' value 'c'

变量声明后可以随时改变值,而常量只能赋值一次,再赋值则会直接报错

爱好玩