012 Integer to Roman (Java)

Given an integer, convert it to a Roman numeral.

Input is guaranteed to being within the range from 1 to 3999.

First to understand the composition of the Roman number

basic word Character	i	v	x	l	c	d	m
The corresponding Arabic numerals are expressed as	1	5	10	50	100	500	1000

1. The same number ligatures, the number represented is equal to the number of these numbers added, such as: ⅲ=3;
2. The small number on the right side of the large number, the number represented is equal to the number of these numbers added, such as: Ⅷ=8, ⅻ=12;
3. Small numbers, (limited to Ⅰ, X, and C) on the left side of large numbers, the number represented is equal to the number of large reduction numbers obtained, such as: ⅳ=4, ⅸ=9;
4. When normal use, the number of ligatures should not exceed three times;
5. Draw a horizontal line over a number, indicating that the number is enlarged by 1000 times times.

Number of groups ruleEditThere are a few notes to be mastered:

1. The basic number Ⅰ, X, C any one, the number of their own use, or put on the right side of the large number of the composition, not more than three; on the left of the large number can only be used one;
2. It is not possible to use any one of the basic digits V, L, D as decimals on the left side of the large number to make up the number by subtracting the method;
3. The small numbers on the left of V and X can only be used Ⅰ;
4. The small numbers on the left of L and C can only be used with X;
5. The small numbers on the left of D and M can only be used in C.

Contrast exampleEdit• single Digit exampleⅠ-1, Ⅱ-2, ⅲ-3, ⅳ-4, ⅴ-5, ⅵ-6, ⅶ-7, Ⅷ-8, ⅸ-9• Example of 10 digitsⅩ-10, ⅺ-11, ⅻ-12, XIII-13, XIV-14, XV-15, XVI-16, XVII-17, XVIII-18, XIX-19, XX-20, XXI-21, XXII-22, XXIX-29, XXX-30, XXXIV-34, XXXV-35, XXXIX-39, XL-40, L-50, LI-51, LV-55, LX-60, LXV-65, LXXX-80, XC-90, XCIII-93, XCV-95, XCVIII-98, XCIX-99• Examples of hundredC-100, CC-200, CCC-300, CD-400, D-500, DC-600, DCC-700, DCCC-800, CM-900, CMXCIX-999• Examples of thousandsM-1000, MC-1100, MCD-1400, MD-1500, MDC-1600, MDCLXVI-1666, MDCCCLXXXVIII-1888, MDCCCXCIX-1899, MCM-1900, MCMLXXVI-1976 , MCMLXXXIV-1984, MCMXC-1990, MM-2000, MMMCMXCIX-3999 reference http://baike.baidu.com/link?url= ikdrmd-342dsxb2crvwmakofiecsd1nx8i4oaznws87wlmvqzikgf-clozquhe3avzvjetr88ju2zw4vvf4k3a

Then the code is as follows

Public  string Getstr (String str,int i,string s1,string s2,string S3) {switch (i) {case 1:str+=s3;break;case 2:STR+=S3 +s3;break;case 3:str+=s3+s3+s3;break;case 4:str+=s3+s2;break;case 5:str+=s2;break;case 6:str+=s2+s3;break;case 7: Str+=s2+s3+s3;break;case 8:str+=s2+s3+s3+s3;break;case 9:str+=s3+s1;break;} return str;}    Public  String inttoroman (int num) {    int ge,shi,bai,qian;    String string= "";    if ((qian=num/1000)!=0) {    num=num%1000;    Switch (Qian) {case    3:string+= "MMM";    Case 2:string+= "MM";    Case 1:string+= "M";    }    }    if ((bai=num/100)!=0) {    num=num%100;    String=getstr (String,bai, "M", "D", "C");    }    if ((SHI=NUM/10)!=0) {    num=num%10;    String=getstr (String,shi, "C", "L", "X");    }    if ((ge=num)!=0) {    string=getstr (string,ge, "X", "V", "I");    }    return string;    }

012 Integer to Roman (Java)