Step 6 of 7

Recursion

A function can call itself. That's recursion. Every recursive function needs a base case that stops, and a step that moves toward it.

int factorial(int n) {
    if (n <= 1) return 1;          // base case
    return n * factorial(n - 1);   // smaller problem
}

Your turn: write int fib(int n) returning the n-th Fibonacci number, where fib(0) = 0, fib(1) = 1 and every later number is the sum of the two before it.

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