What is recursion?
Recursion is a widely used phenomenon in computer science used to solve complex problems by breaking them down into simpler ones. Recursion is a process by which a function calls itself directly or indirectly. The corresponding function is called as recursive function.
Using recursive algorithms, certain complex problems can be solved quite easily.
What is a base condition in recursion?
In a recursive function, the solution to the base case is provided and the solution of the bigger problem is expressed in terms of smaller problems.
The role of the base condition is to stop a recursive function from executing endlessly – once a pre-specified base condition is met, the function knows it’s time to exit.
#include <iostream>using namespace std;int fact(int n){if (n <= 1) // base casereturn 1;elsereturn n*fact(n-1);}int main() {cout << fact(5) << endl;}
In the example above, we can compute the factorial of n if we know the factorial of (n-1). The base case for this factorial function would be n = 0. We return 1 when n = 0, the base case, is reached.
Every recursive program must have a base case to make sure that the function will terminate at some point. Missing the base case results in unexpected behavior.
Simply put, the idea behind recursion is to represent a larger problem in terms of one or more smaller problems and add one or more base conditions that stop the recursion from looping endlessly.
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