Recursion happens when control enters a loop that has no exit. This can happen when a method invokes itself or when a pair of methods invoke each other. It can be a useful tool, but unless the method includes a provision to break out of the recursion and ``++return++``, the recursion will continue until the stack overflows and the program crashes.

== Noncompliant Code Example

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def my_pow(num, exponent):  # Noncompliant
    num = num * my_pow(num, exponent - 1)
    return num  # this is never reached
----

== Compliant Solution

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def my_pow(num, exponent):  # Compliant
    if exponent > 1:
      num = num * my_pow(num, exponent - 1)
    return num
----
