Conditional Constructs in Java

Chapter 9

Conditional Constructs in Java

Class 9 - Logix Kips ICSE Computer Applications with BlueJ

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Java Programs - Special Two-Digit Number

A special two-digit number is such that when the sum of its digits is added to the product of its digits, the result is equal to the original two-digit number.

Example: Consider the number 59.
Sum of digits = 5 + 9 = 14
Product of digits = 5 * 9 = 45
Sum of the sum of digits and product of digits = 14 + 45 = 59

Write a program to accept a two-digit number. Add the sum of its digits to the product of its digits. If the value is equal to the input number, display the message "Special 2 - digit number" otherwise, display the message "Not a special two-digit number".

import java.util.Scanner;
 
public class SpecialTwoDigitNumber {
    public static void main(String[] args) {
 
        Scanner sc = new Scanner(System.in);
 
        System.out.print("Enter a two-digit number: ");
        int num = sc.nextInt();
 
        // Extract digits
        int tens = num / 10;
        int units = num % 10;
 
        // Calculate sum and product of digits
        int sum = tens + units;
        int product = tens * units;
 
        // Check special condition
        if (sum + product == num) {
            System.out.println("Special 2-digit number");
        } else {
            System.out.println("Not a special two-digit number");
        }
 
        sc.close();
    }
}
 

Output 1 : 
SAMPLE INPUT : 
Enter a two-digit number: 59

SAMPLE OUTPUT : 
Special 2-digit number

Output 2 : 
SAMPLE INPUT : 
Enter a two-digit number: 23

SAMPLE OUTPUT : 
Not a special two-digit number

Explanation

1. Input

• The program accepts a two-digit number from the user.

2. Digit Extraction

         int tens = num / 10;

         int units = num % 10;

• Tens digit is obtained using division.
• Units digit is obtained using modulus operator.

3. Sum & Product Calculation

          int sum = tens + units;

          int product = tens * units;

4. Special Number Check

         if (sum + product == num)

• If (sum of digits + product of digits) equals the original number, it is a special two-digit number.