Different type of numbers generally asked in Java ICSE Board exams

1. Disarium Number

2. Amicable Pair

3. Unique Number

4. BUZZ number

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Question 1 : Disarium Number

Write a java program to check whether the entered number is a Disarium Number. A number is called a Disarium if sum of the digits powered with its respective positions is equal to original number itself.

For example: 175 is a Disarium number.
175 = 1¹+7²+5³ = 1+49+125 = 175
Here in this program we will be using Scanner class to take the input from the user.

import java.util.Scanner;
public class Disarium 
{
public static void main(String args[])
{
Scanner sc = new Scanner(System.in);
System.out.print("Enter a number : ");
int num = sc.nextInt();
int temp = num, rem = 0, sum = 0;//to keep original number intact taking temp 
String s = Integer.toString(num);  
int len = s.length();  //to calculate the length of number converted to string
while(temp>0)
{
rem = temp % 10;  
sum = sum + (int)Math.pow(rem,len--);
temp =  temp/10;
}
if(sum == num) //to check whether the original number is equal to the sum
System.out.println("Disarium Number.");
else
System.out.println("Not a Disarium Number.");
}

}

Output of the code:

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Question 2 : Amicable Pair

Write a java program to check whether the entered pair is a Amicable Pair. Amicable pair are so related that sum of proper divisors of each is equal to other number.

Amicable numbers are:(220,284), (1184,1210), (2620,2924), (5020,5564), etc.
For Example: 220 and 284 are amicable pair.
Divisors of 220 = 1,2,4,5,10,11,20,22,44,55,110
Sum of divisors of 220 = 1+2+4+5+10+11+20+22+44+55+110  = 284
Divisors of 284 = 1,2,4,71,142
Sum of divisors of 284 = 1+2+4+71+142 = 220
Here 284 is not equal to 220. And sum of divisors is equal to other number itself.

import java.util.Scanner;
public class AmicableNumber 
{
public static void main(String args[]) 
{
Scanner sc = new Scanner(System.in);
System.out.print("Enter first number: ");
int num1 = sc.nextInt();
System.out.print("Enter second number: ");
int num2 = sc.nextInt();
int sumNum1 = 0, sumNum2 = 0;
for(int i=1;i<num1;i++) 
{
if (num1%i==0)
sumNum1 = sumNum1+i;
}
for(int i=1;i<num2;i++) 
{
if (num2%i==0)
sumNum2 =sumNum2+i;
}
if ((sumNum1 == num2) && (sumNum2 == num1) && (num1!=num2))
System.out.println("Amicable pair");
else
System.out.println("Not amicable pair");
}
}

Output of the code:

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Question 3 : Unique Number

Write a java program to check whether the entered number is a Unique Number or not. A number that does not have any duplicate digit is called Unique Number.

For example: 12345, 3456 are unique numbers.

122323, 2323 are not unique numbers.

import java.util.Scanner;

public class UniqueNumber 

{

public static void main(String args[])

{

Scanner sc = new Scanner(System.in);

System.out.println("Enter a number: ");

int num = sc.nextInt();

boolean flag = false;

String str = Integer.toString(num);

int len = str.length();

for(int i=0;i<len-1;i++)

{

for(int j=i+1;j<len;j++)

{

if(str.charAt(i)==str.charAt(j))

{

flag = true;

break;

}

}

}

if(flag==false)

System.out.println("Unique Number");

else

System.out.println("Not Unique");

}

}

Output of the code:

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Question 4 : BUZZ Number

Write a java program to check whether the entered number is a BUZZ number or not. BUZZ number are those numbers whose last digit is 7 or divisible by 7.

import java.util.Scanner;

public class Buzz 

{

public static void main(String[] args) 

{

Scanner sc = new Scanner(System.in);

System.out.print("Enter a number : ");

int num = sc.nextInt();

if(num%7==0 || num%10==7)

System.out.println(num+" is BUZZ number.");

else

System.out.println(num+" is not BUZZ number.");

}

}

Output of the code: