Fascinating Number program

https://java4school.com/frequency-of-letters

``````import java.util.*;
class Fascinating
{
void mergnum(int n)
{
int a  = n*2;int mergnum;
int b = n*3;
String n1,n2,n3;String m;
n1 = Integer.toString(n);
n2 = Integer.toString(a);
n3 = Integer.toString(b);
m = n1+n2+n3;
mergnum = Integer.valueOf(m);
}
boolean isFacinating()
{
int c = 0;
int i = 0;
char ch[] = {'1','2','3','4','5','6','7','8','9'};
char temp = ch;
int flag = 0;
while(mergnum>0)
{ int rem = mergnum%10;
if(rem == (int)temp[i])
{
temp[i]=' ';
c++;
i++;
}
else
{
i++;
}
mergnum = mergnum/10;
if(c==9)
{
return true;
}
else
{
return false;
}
}
public static void main()
{
Fascinating obj  = new Fascinating();
Scanner sc = new Scanner(System.in);
System.out.println("Enter the lower limit greter then 99");
int lo = sc.nextInt();
System.out.println("Enetr the upper limit less then 10000");
int ul = sc.nextInt();
int count = 0; System.out.println("THE FASCINATING NUMBERS ARE ");
if(ul<lo||ul>10000||lo<99)
{
System.out.println("INVALID INPUT");
}
else
{

for(int j = lo;j<ul;j++)
{
if(isFascinating(j))
{
if(count>0)
{
System.out.println(j);}

if(count==0)
{
System.out.println("NULL");}

}
count++;
System.out.println("THE FREQUENCY OF THE FASCINATING NUBERS IS : "+count);
}}}
``````