Iterative Constructs in Java

Chapter 9

Iterative Constructs in Java

Class 10 - Logix Kips ICSE Computer Applications with BlueJ

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Java Program: Check Pronic Number

22. Write a program to input a number and check and print whether it is a Pronic number or not. (Pronic number is a number which is the product of two consecutive integers.)
Example:   12 = 3 x 4
                 20 = 4 x 5
                 42 = 6 x 7

Program Title: Check Pronic Number

import java.util.Scanner;
 
public class PronicNumber {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
 
        System.out.print("Enter a number: ");
        int num = sc.nextInt();
        boolean isPronic = false;
 
        for (int i = 0; i <= num / 2; i++) {
            if (i * (i + 1) == num) {
                isPronic = true;
                break;
            }
        }
 
        if (isPronic) {
            System.out.println(num + " is a Pronic Number.");
        } else {
            System.out.println(num + " is NOT a Pronic Number.");
        }
 
        sc.close();
    }
}
 

Sample Input / Output 1:
Enter a number: 12
12 is a Pronic Number.

Sample Input / Output 2:
Enter a number: 15
15 is NOT a Pronic Number. 

📝 Explanation

1. A Pronic number is the product of two consecutive integers:
2. n = i * (i + 1)
3. Loop runs from i = 0 to num / 2 (because i * (i+1) cannot exceed num)
4. If we find i * (i+1) == num, the number is pronic.
5. If no such i exists, the number is not pronic.