16. 加一

#include <iostream>

int main()
{
    using std::cout;
    int a = 20;
    int b = 20;
    cout << "a      = " << a << ":      b = " << b << "\n";
    cout << "a++    = " << a++ << ":    ++b = " << ++b << "\n";
    cout << "a      = " << a << ":      b = " << b << "\n";
}