Number Convert

Hi

import java.io.*;

public class NumberToWord {
String string;
String a[]={"","one","two","three","four","five","six","seven","eight","nine",};
String b[]={"hundred","thousand","lakh","crore"};
String c[]={"ten","eleven","twelve","thirteen","fourteen","fifteen","sixteen","seventeen","eighteen","ninteen",
};
String d[]={"twenty","thirty","fourty","fifty","sixty","seventy","eighty","ninty"};

public String convertNumber(int count){
int in=1;
int num ;
string="";
while (count != 0){
switch (in){
case 1:
num = count % 100;
passString(num);
if( count > 100 && count % 100 != 0 ){
displayOutput("and ") ;
}
count /= 100 ;
break ;
case 2:
num = count % 10 ;
if ( num != 0 ){
displayOutput(" ") ;
displayOutput(b[0]);
displayOutput(" ");
passString(num);
}
count /= 10 ;
break ;

case 3 :
num = count % 100 ;
if ( num != 0 ){
displayOutput(" ") ;
displayOutput(b[1]) ;
displayOutput(" ") ;
passString(num) ;
}
count /= 100 ;
break ;
case 4 :
num = count % 100 ;
if (num != 0){
displayOutput(" ");
displayOutput(b[2]);
displayOutput(" ");
passString(num) ;
}
count /= 100 ;
break ;

case 5 :
num = count % 100 ;
if (num != 0){
displayOutput(" ") ;
displayOutput(b[3]) ;
displayOutput(" ") ;
passString(num) ;
}
count /= 100 ;
break ;

}
in++ ;
}
return string;
}

public void passString(int number){
int num, q ;
if (number < 10 ){
displayOutput(a[number]) ;
}
if (number > 9 && number < 20 ){
displayOutput(c[number-10]) ;
}
if ( number > 19 ){
num = number % 10 ;
if ( num == 0 ){
q = number / 10 ;
displayOutput (d[q-2]) ;
}
else{
q = number / 10 ;
displayOutput(a[num]);
displayOutput(" ") ;
displayOutput(d[q-2]);
}
}
}

public void displayOutput(String s){
String t ;
t= string ;
string= s ;
string+= t ;
}

public static void main(String args[]) throws IOException{
BufferedReader buff = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Display massage number to Text!");
NumberToWord num=new NumberToWord();
System.out.println("Number to word: "+num.convertNumber(10)+".");
System.out.println("Number to word :"+num.convertNumber(15)+".");
System.out.println("Number to word :"+num.convertNumber(50)+".");
System.out.println("Number to word :"+num.convertNumber(99)+".");
System.out.println("Number to word :"+num.convertNumber(150)+".");
System.out.println("Number to word :"+num.convertNumber(234)+".");
System.out.println("Number to word :"+num.convertNumber(250)+".");
}
}