C++语言开发示例：02. 计数

#include <iostream>

void countdown(int n);

int main()
{
    countdown(4);
}

void countdown(int n)
{
    using namespace std;
    cout << "Counting down ..." << n << endl;
    if (n > 0)
        countdown(n - 1);
    cout << n << ": Kaboom!\n";
}