roman numeral special cases

[flameZero]

hey guys i was wonderin if u could help me out.
i am doing a roman numeral assignment and i am stuck on the special cases ( IX,IC,IV,etc) i have them in a FOR loop and i tested it out by outputtin "hello" before the calculations but the program doesnt see the fact that IX is 9 instead of 11.i have included my java file.

code:

import javax.swing.JOptionPane;  import java.io.*; public class Assignment5c { public static void main(String[] args) {                 String romannum;         int romantotal;         int x;         int Y;         int lengthOfX;         String substring=" ";         char quit='y';         int i;         while (quit=='y'){         romantotal=0;         romannum=Keyin.inString("enter a roman numeral:");         lengthOfX = romannum.length();         for ( i=0; i<lengthOfX;i=i+1){          Y = romannum.charAt(i);         int asciivalue=(int)Y;         switch (asciivalue){         case 73:         romantotal+=1;break;         case 67:         romantotal+=100;break;         case 88:         romantotal+=10;break;         case 76:         romantotal+=50;break;         case 86:         romantotal+=5;break;         case 68:         romantotal+=500;break;         case 77:         romantotal+=1000;break; } } for(i=0;i<lengthOfX-1;i+=1){         substring=romannum.substring(i,i+1);         System.out.println ("hello");                 if(substring.equals("IV"))                         romantotal-=2;                 if(substring.equals("IX"))                         romantotal-=2;                 if(substring.equals("IC"))                         romantotal-=2;                 if(substring.equals("IL"))                         romantotal-=2;                 if(substring.equals("ID"))                         romantotal-=2;                 if(substring.equals("IM"))                         romantotal-=2;                 if(substring.equals("XL"))                         romantotal-=20;                 if(substring.equals("XC"))                         romantotal-=20;                 if(substring.equals("XD"))                         romantotal-=20;                 if(substring.equals("XM"))                         romantotal-=20;                 if(substring.equals("CD"))                         romantotal-=200;                 if(substring.equals("CM"))                         romantotal-=200;                                } JOptionPane.showMessageDialog(null,"the roman numeral entered was: "+romannum+" the total is: " + romantotal); quit=Keyin.inChar("would you like to try again?(y/n):"); } } }

can you help me see what i did wrong. i believe it is a logic error but i cant figure it out . thanks in advance for any tips.