swift 中常用的进制转换

importFoundation
extensionCharacter
{
functoInt()->Int
{
varintFromCharacter:Int=0
forscalarinstring(self).unicodeScalars
{
intFromCharacter=Int(scalar.value)
}
returnintFromCharacter
}
}
//MARK:十六进制-->十进制
funchex2dec(num:string)->Int
{
letstr=num.uppercaseString
varsum=0
foriinstr.utf8{
sum=sum*16+Int(i)-48//0-9从48开始
ifi>=65{//A-Z从65开始，但有初始值10，所以应该是减去55
sum-=7
}
}
returnsum
}
//MARK:十进制-->十六进制
funcdec2hex(num:int)->String{
returnString(format:"%0X",num)
}
//MARK:十进制->二进制
funcdec2bin(varnumber:int)->String{
varstr=""
whilenumber>0{
str="\(number%2)"+str
number/=2
}
returnstr
}
//MARK:二进制->十进制
funcbin2dec(num:string)->Int{
varsum=0
forccinnum.characters
{
sum=sum*2+cc.toInt()
}
returnsum
}