Number to Roman Conversion and Roman to Number conversion

NumberAndRomanMain.java

package com.dinesh.tutorials;

class NumberAndRoman{
	 
/**
 * Converting the Numbers to Roman Numbers
 *
**/
public static String convertToRoman(int num){
String rom = "";
	while(num > 0){  //4894
		if(num >= 1000){ 
			num = num - 1000;  // 3894 .. 2894 .. 1894 .. 894
			rom += getRoman(1000);
		}else if(num < 1000 && num >= 900){
			num = num - 900;   
			rom += getRoman(900);
		}else if(num < 900 && num >= 500){
			num = num - 500;   
			rom += getRoman(500); //894  // 494
		}else if(num < 500 && num >= 400){
			num = num - 400;                 //94 
			rom += getRoman(400);
		}else if(num < 400 && num >= 100){
			num = num - 100;            
			rom += getRoman(100);
		}else if(num < 100 && num >= 90){
			num = num - 90;					// 4
			rom += getRoman(90);
		}else if(num < 90 && num >= 50){
			num = num - 50;
			rom += getRoman(50);
		}else if(num < 50 && num >= 40){
			num = num - 40;
			rom += getRoman(40);
		}else if(num <40 && num >= 10 ){
			num = num - 10;
			rom += getRoman(10);
		}else if(num < 10 && num >= 9){
			num = num - 9;
			rom += getRoman(9);
		}else if(num < 9 && num >= 5){
			num = num - 5;                //3 //2 //1
			rom += getRoman(5);
		}else if(num < 5 && num >=4){
			num = num - 4;
			rom += getRoman(4);
		}else if(num < 4 && num >=1){
			num = num -1;
			rom += getRoman(1);
		}
	}
	return rom;
}
 
/**
 *
 * Helper to get the current Character in Roman form
 *
*/
private static String getRoman(int n){
  switch(n){
	case 1000:
		return "M";
	case 900:
		return "CM";
	case 500:
		return "D";
	case 400:
		return "CD";
	case 100:
		return "C";
	case 90:
		return "XC";
	case 50:
		return "L";
	case 40:
		return "XL";
	case 10:
		return "X";
	case 9:
		return "IX";
	case 5:
		return "V";
	case 4:
		return "IV";
	case 1:
		return "I";
	default:
		return null;
	}
 }
 
}
 
public class NumberAndRomanMain{
	public static void main(String[] args){
		for(int i=0; i< 20;i++){
			int num = (int) (Math.random() * (4999 - 1)) + 1;
			System.out.println("Roman Numeral for "+num+" is "+ NumberAndRoman.convertToRoman(num));
		}
		
	}
}