Recursion is a powerful concept in programming that allows a function to call itself repeatedly until a specific condition is met. This can be a useful tool in solving complex problems, but it can also be tricky to understand and implement.

In Ruby, recursion is typically implemented using a base case, which is a condition that will cause the recursive function to stop calling itself, and a recursive case, which is the logic for the function to call itself again with a modified set of inputs.

Here is a simple example of a recursive function in Ruby, which we already visited this previous post, that calculates the factorial of a given number:

def factorial(n)
  if n == 0 || n == 1
    return 1
    return n * factorial(n-1)

puts factorial(5) # Outputs 120

In this example, the base case is when n is 0 or 1, in which case the factorial is simply 1. In the recursive case, the function calls itself with the input of n-1, effectively breaking down the problem into smaller and smaller pieces until it reaches the base case.

One important thing to keep in mind with recursion is to ensure that the base case is properly defined, otherwise the function will continue to call itself indefinitely and result in a stack overflow error.

While recursion can be a useful tool in solving complex problems, it is important to consider its potential drawbacks, such as increased memory usage and the potential for slower performance compared to iterative solutions. As with any programming concept, it is important to carefully weigh the benefits and drawbacks before deciding to implement recursion in a specific situation.