kotlin实现罗马数字和阿拉伯数字转换

来源：互联网发布：轴承查询软件下载编辑：程序博客网时间：2024/06/05 01:08

1.罗马数字转阿拉伯数字

遍历罗马数字的每一位，若当前位比前一位小，则在结果中加上当前位

否则在结果中减去前一位的两倍再加上当前位

2.阿拉伯数字转罗马数字

先构造map

mapOf(1000 to "M",900 to "CM",500 to "D",400 to "CD",100 to "C",90 to "XC",50 to "L",40 to "XL",10 to "X",9 to "IX",5 to "V",4 to "IV",1 to "I")

遍历map

若当前数字大于第i个数字

将第i个数字对应的字母加入结果中，当前数字－＝第i个数字

val romeChar=mapOf(        'I' to 1,        'V' to 5,        'X' to 10,        'L' to 50,        'C' to 100,        'D' to 500,        'M' to 1000)class RomeNumber private constructor(){    constructor(number:String):this(){        this.number=number    }    var number:String=""        set(value){            if(value.toCharList().any{!romeChar.containsKey(it)}) throw object :Exception("It is not a legal Rome Number"){ } else $number=value.toUpperCase()        }    public fun toArabicNumber():Int{        var lastNumber=0        var sum=0        number.toCharList().forEach {            var value:Int?=romeChar.get(it)            if (value!!>lastNumber) {sum-=lastNumber*2;sum+=value;}else sum+=value            lastNumber=value        }        return sum    }    override fun toString(): String {        return number    }}fun Int.toRomeNumber():RomeNumber{    val additionMap = mapOf(1000 to "M",900 to "CM",500 to "D",400 to "CD",100 to "C",90 to "XC",50 to "L",40 to "XL",10 to "X",9 to "IX",5 to "V",4 to "IV",1 to "I")    val sb=StringBuilder()    var temp=this    while (temp != 0) {        additionMap.forEach {            while (temp >= it.getKey()) {                sb.append(it.getValue())                temp -= it.getKey()            }        }    }    return RomeNumber(sb.toString())}

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