Question

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.

Answer 1

Answer:

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);

       }