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Examples of Recursive functions

I have been trying to research recursion in programming as a concept (though I am specifically studying Java) and this is what I got to understand the best:

In real life for example, recursion is when we put two mirrors infront of each other and the images produced between them are recursive.

But I don’t get this algorithm in programming?
Can someone give me a simplified example to understand recursion ?

Answer 1

Basically, a function is recursive when

1. A function has a simple base case, and when
2. All other cases have rules which reduce to the base case.

As an example, to calculate an factorial:

public static long factorial(int i)
{
    // This is the base case
    if(i == 0)
    {
         return 1;
    }
    else
    {
        // This reduces the problem to something closer to the base case
        return i * factorial(i - 1);
    }
}