In the topic of recursion, an important concept that is often brought up is tail recursion. A special kind of recursion, where the function's recursive call is the last operation it performs. It's termed as 'tail' because there's nothing to do after the function calls itself - the call to the recursive function is literally at the 'tail end' of the function.

One of the primary benefits of tail recursion is its efficient utilization of memory. In simple recursion, for every recursive call, the system must 'remember' previous calculations leading up to that call. This can consume considerable memory and lead to a stack overflow for in-depth recursion chains. However, in tail recursion, the calculations are done upfront, with the result passed as an argument to the recursive call. This allows the system to discard old stack frames as new ones are created, effectively performing a 'swap' operation instead of a 'push', significantly reducing the risk of a stack overflow and providing a more efficient execution flow.

Algorithms that are implemented with tail recursion can be directly mapped to iterations, and hence, are preferred in programming, especially in AI and finance-related calculations.

Let's take the example of a recursive function for calculating the factorial of a number. The tail-recursive version of this function would be as below:

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#include <iostream>

using namespace std;

​

// Tail-recursive function to calculate factorial

int factorial(int n, int a = 1) {

    if (n > 1)

        return factorial(n - 1, n * a);

    else

        return a;

}

​

int main() {

    int num = 5;

    cout << "Factorial of " << num << " is " << factorial(num) << endl;

    return 0;

}