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Ruby program to calculate the Greatest Common Divisor

Last Updated : December 15, 2025

Problem Solution

In this program, we will read two integer numbers from the user, and then we will find the Greatest Common Divisor and print the result.

Program/Source Code

The source code to calculate the Greatest Common Divisor is given below. The given program is compiled and executed successfully.

# Ruby program to calculate the 
# Greatest Common Divisor

num1=0
num2=0
rem=0
x=0
y=0

print "Enter number1: ";
num1 = gets.chomp.to_i;  

print "Enter number2: ";
num2 = gets.chomp.to_i;  

if (num1 > num2) 
    x = num1;
    y = num2;
else 
    x = num2;
    y = num1;
end

rem = x % y;

while (rem != 0) 
    x = y;
    y = rem;
    rem = x % y;
end

print "Greatest Common Divisor is: ",y;

Output

Enter number1: 24
Enter number2: 21
Greatest Common Divisor is: 3

Explanation

In the above program, we created five variables num1, num2, rem, x, y initialized with 0. Then we read values num1 and num2 from the user. After that, we found the Greatest Common Divisior and printed the result.

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