How exactly does tail recursion work?

Question

I almost understand how tail recursion works and the difference between it and a normal recursion. I only don\'t understand why it doesn\'t

Answer 1

Tail recursion can usually be transformed into a loop by the compiler, especially when accumulators are used.

// tail recursion
int fac_times (int n, int acc = 1) {
    if (n == 0) return acc;
    else return fac_times(n - 1, acc * n);
}

would compile to something like

// accumulator
int fac_times (int n) {
    int acc = 1;
    while (n > 0) {
        acc *= n;
        n -= 1;
    }
    return acc;
}