Swift学习笔记之逻辑分支与循环体

if(a>0)NSlog(@"yes");

 //如果一个成年人带了省份证才能上网 func cherk(age:Int hasCard:Bool){  if age >= 18{   if hasCard{   print("老板,开个机")   }else{   print("回家拿身份证")   }  else{   print("未成年不能上网")  } } func cherkGuard(age:Int hasCard:Bool){  guard age >= 18 else {  print("老板,开个机")  return  }  guard hasCard else {  print("回家拿省份证")  return  }  print("未成年不能上网")}

let range = 0...10//闭区间代表区间0~10let range1 = 0..<10半开半闭区间代表区间0~9

let point = (10,15)switch point{  case (0,0)  print("坐标在原点")  case (1...10,1...10)//可在元祖中加上区间  print("坐标X,Y在1...10之间")  case (,0)//可在元祖中加上区间  print("坐标X在X轴上")  default   print("其它")  }

let point = (10,15)switch point{  case (var x,0)  print("x=/(x)")//point中的x赋值给x  case (10,var y) print("y=/(y)")//point中的y赋值给y  case var(x,y)  print("x=/(x) y=/(y)")//point中的xy赋值给xy  default   print("其它")}

let point = (100,10)switch point{  //只有where后面的条件语句表达式为真财赋值并执行case后面的语句  case var( x,y) where x > y  print("x=/(x) y=/(y)")  default   print("其它")}

 for _ in 0..<10{ //_代表忽略的意思 print("xxx")  }

var i =10while i > 0{i-=1;print (i)}

repeat {//swift 中不用do ,do在swift有特殊含义,用于捕捉异常 i +=1 print(i)}while i < 10