C++/STL Basics/binary function

std::binary_function

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/* The following code example is taken from the book

* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/

1. include <iostream>
2. include <vector>
3. include <algorithm>
4. include <iterator>

using namespace std; // include self-defined fopow<>

1. include <functional>
2. include <cmath>

template <class T1, class T2> struct fopow : public std::binary_function<T1, T2, T1> {

   T1 operator() (T1 base, T2 exp) const {
       return std::pow(base,exp);
   }

};

int main() {

   vector<int> coll;
   // insert elements from 1 to 9
   for (int i=1; i<=9; ++i) {
       coll.push_back(i);
   }
   // print 3 raised to the power of all elements
   transform (coll.begin(), coll.end(),           // source
              ostream_iterator<float>(cout," "),  // destination
              bind1st(fopow<float,int>(),3));     // operation
   cout << endl;
   // print all elements raised to the power of 3
   transform (coll.begin(), coll.end(),           // source
              ostream_iterator<float>(cout," "),  // destination
              bind2nd(fopow<float,int>(),3));     // operation
   cout << endl;

} /* 3 9 27 81 243 729 2187 6561 19683 1 8 27 64 125 216 343 512 729

*/        
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