swift学习笔记(2)--控制语句与循环语句

1.控制语句
(1).if

var ifNum = 1if 1 == ifNum{    print("true")}else{    print("false")}

(2).switch

switch ifNum{case 0:    print("213")case 1:    print("true")case 2:    print("213")default:    print("sb")}var lei = 38switch ifNum{//双重判断,两个条件必须同时满足才能执行代码块case 1..<20 where 38 == lei: //where:且判断关键字 , 相当于&&    print("1")case 10:    print("2")default:    print("error")}// 元组分解,加上"_"的作用是忽略值var point = (0 , 5)switch point{case (_ , 0):    print("1")case (0 , _):    print("2")default:    print("error")}

2.循环语句

for var i = 0; i < 10; i++ {    i += 1}var sum = 1while sum < 5{    sum += 1}var sum1 = 1repeat {    sum1 += 1} while sum1 < 5;