BlueJ Program On Unique Digit Integer Within A Specified Range

This BlueJ program was set in the ISC Computer Science Practical Examination of 2008.The program is as follows:

A unique digit integer is a positive integer (without leading zeros) with no

duplicate digits. For example 7, 135,214 are all unique digit integers whereas 33,3121,300 are not.

Given two positive integers, m and n where m < n, write a program to determine how many unique digit integers are there in the range m and n (both inclusive)and display them.

Sample Data

Input:

m=100

n=120

Output:

The unique digit integers are:

102,103,104,105,106,107,108,109,120

Frequency of unique digit integers is : 9

import java.io.*;

class Digit

{

 int k,x,i,j,m,n,c,arr[],index;

 BufferedReader br;

  public static void main(String args[])throws IOException

   {

  Digit ob=new Digit();

  ob.take();

  ob.show();

  }

  Digit()

  {

   br=new BufferedReader(new InputStreamReader(System.in));

   arr=new int[1000];

   c=0;

   index=0;

   }

public void take()throws IOException

{

 while(true)

 {

 System.out.println("Enter the Lower range:");

m=Integer.parseInt(br.readLine().trim());

System.out.println("Enter the Upper range:");

n=Integer.parseInt(br.readLine().trim());

if(m< n)

break;

}

}

void show ()

{

System.out.println("The unique digit integers are:");

for(i=m;i< =n;i++)

{

 index=0;

 for(j=i;j> 0;j=j/10)

 {

  x=j%10;

  for(k=0;k< index;k++)

  {

   if (arr[k]==x)

   break;

   }

   if(k< index)

   break;

   else

   arr[index++]=x;

   }

   if (j==0)

   {

    c++;

    System.out.print(" "+i);

    }

    }

   

System.out.println("\nFequency of unique digit integers is :"+ c);

 }

 }

  

 Variable Descriptions:

‘m’ – This will hold the lower range

‘n’ – it will hold the upper range

‘i’, ‘j’, ‘k’ are loop control variables

‘x’ is used to hold digits

‘c’ is the counter to count unique digit numbers

‘arr[]’ is used to check the numbers for unique digits

‘index’ is the array index of the array ‘arr[]’

‘br’  BufferedReader class object

 Algorithm of the program

Step 1: Take the lower range and store in ‘m’

Step 2: Take the upper range and store in ‘n’

Step 3: If ‘m’ is not less than ‘n’ repeat steps 1 and 2, otherwise go to Step  4

Step 4: Repeat the following steps by assigning values starting from ‘m’ upto ‘n’ on ‘i’

Step 5: Set ‘0’ on ‘index’

Step 6: Assign the value of ‘i’ on ‘j and repeat the following steps until j becomes ‘0’

Step 7: Retrieve a digit from j and check whether it is present in the array ‘arr’

Step 8: If it is present, go to Step 4

Step 9: If not present assign the digit in the array ‘arr’ and increment ‘index’ by ‘1’

Step 10: Eliminate the digit from ‘j’ and go to Step &

Step 11: If ‘j’ becomes ‘0’, display the value of ‘I’ and increment ‘c’ by ‘1’

Step 12: Go to Step 4, if ‘I’ becomes greater than ‘n’ go to Step 13

Step 13: Display ‘c’

Related Post: BlueJ Programs on Number