// This code demonstrates use of member initialization lists in constructors.
//
// When should you use member initialization?
// • When you have a non-default initial value for your member variable.
// • When you want to emphasize the default initial value.
// • When the member variable is expensive to construct, and you
//   have a non-default initial value to put in it.
//
// When must you use member initialization?
// • When the member variable is only initializable, and not assignable:
//   - a const variable
//   - a reference variable
//   - an object without a default constructor
//   - initializing a base class
//
// Member variables are constructed in declaration order,
// not member initialization list order.

#include <iostream>

using namespace std;

class Ratio {
  public:
    Ratio() : top(0), bottom(1) { }
    Ratio(int a) : top(a), bottom(1) { }
    Ratio(int a, int b) : top(a), bottom(b) { }

    // Ctor delegation:
    // BAD: Ratio() { Ratio(0,1); }
    // GOOD: Ratio() : Ratio(0,1) { }
    // GOOD: Ratio(int a) : Ratio(a,1) { }

  private:
    int top, bottom;
};

int main() {
    Ratio f;
}