变量的赋值
//变量声明
var r,pi,area,circ:Float
//变量赋值
r=5
pi=3.14
////带算术操作的赋值
circ=pi*2*r
area=pi*r*r
//变量使用
print(r,pi,area,circ)
变量的取值范围
import Foundation
//数据类型的值范围使用
var myInt32Min:Int = -2147483648
var myInt32Max:Int32 = 2147483647;
var myint64: Int64 = 2147483647;
print(myint64);
//输出数据类型的取值范围
print(Int32.min) //-2147483648
print(Int32.max) //2147483647
print(Int64.min) //-9223372036854775808
print(Int64.max) //9223372036854775807
print(Int16.min) //-32768
print(Int16.max) //32767
print(UInt16.min)//0
print(UInt16.max)//65535
print(Float.greatestFiniteMagnitude);
print(Float.leastNormalMagnitude);
//print(FLT_MAX)
//print(FLT_MIN)
print(Double.greatestFiniteMagnitude)
print(Double.leastNormalMagnitude)
//print(DBL_MAX)
//print(DBL_MIN)