functors/compose1.hpp

The following code example is taken from the book
C++ Templates - The Complete Guide
by David Vandevoorde and Nicolai M. Josuttis, Addison-Wesley, 2002
© Copyright David Vandevoorde and Nicolai M. Josuttis 2002


template <typename FO1, typename FO2>
class Composer {
  private:
    FO1 fo1;  // first/inner function object to call
    FO2 fo2;  // second/outer function object to call
  public:
    // constructor: initialize function objects
    Composer (FO1 f1, FO2 f2)
     : fo1(f1), fo2(f2) {
    }
 
    // ``function call'': nested call of function objects
    double operator() (double v) {
        return fo2(fo1(v));
    }
};