Write a code that calculates the Greatest Common Divisor (GCD) of two positive integers (user-defined inputs). Include an exception such that if their greatest common divisor equals to 1, it prints out the message, saying its GCD is 1.

This program is written using Java programming language

import java.util.*;

public class calcGcd

{

   public static void main (String [] args)

   {

       int num1, num2;

       Scanner input = new Scanner(System.in);

       //Input two integers

       num1 = input.nextInt();

       num2 = input.nextInt();

       //Get least of the two integers

       int least = num1;

       if(num1 > num2)

       {

           least = num2;

       }

       //Initialize gcd to 1

       int gcd = 1;

       //Calculate gcd using for loop

       for(int i=1;i<=least;i++)

       {

           if(num1%i == 0 && num2%i == 0)

           {

               gcd = i;

           }

       }

       if(gcd == 1)

       {

           System.out.print("GCD is 1");

       }

       else

       {

           System.out.print("GCD is "+gcd);

       }

   }

}

Explanation:

To calculate the GCD, the program uses a for loop that iterates from 1 to the smaller number of the user input.

Within this iteration, the program checks for a common divisor of the two user inputs by the iterating element

The GCD is then displayed afterwards;

However, if the GCD is 1; the program prints the message "GCD is 1"

Line by Line Explanation

This line declares two integer numbers

       int num1, num2;

This line allows user the program to accept user defined inputs        

Scanner input = new Scanner(System.in);

The next two line allows gets inputs from the user

       num1 = input.nextInt();

       num2 = input.nextInt();

To calculate the GCD, the smaller of the two numbers is needed. The smaller number is derived using the following if statement

       int least = num1;

       if(num1 > num2)

       {

           least = num2;

       }

The next line initializes GCD to 1

       int gcd = 1;

The GCD is calculated using the following for loop

The GCD is the highest number that can divide both numbers

       for(int i=1;i<=least;i++)

       {

           if(num1%i == 0 && num2%i == 0)

           {

               gcd = i;

           }

       }

The following is printed if the calculated GCD is 1

       if(gcd == 1)

       {

           System.out.print("GCD is 1");

       }

Otherwise, the following is printed

       else

       {

           System.out.print("GCD is "+gcd);

       }

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