Finding Greatest Common Divisor Using Recursion

# Introduction

In mathematics, the greatest common divisor (GCD) of two numbers is commonly defined as the largest positive integer that divides the two numbers without leaving a remainder. In this lab, we will learn to write a C program to find the GCD of two numbers using recursion.

> Note: You need to create the file `~/project/main.c` yourself to practice coding and learn how to compile and run it using gcc.

cd ~/project
# create main.c
touch main.c
# compile main.c
gcc main.c -o main
# run main
./main