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
#include <vector>
#include <iostream>
#include <cstdlib>
// wrapper for function pointers to function objects
template<int (*FP)()>
class FunctionReturningIntWrapper {
public:
int operator() () {
return FP();
}
};
// example function to wrap
int random_int()
{
return std::rand(); // call standard C function
}
// client that uses function object type as template parameter
template <typename FO>
void initialize (std::vector<int>& coll)
{
FO fo; // create function object
for (std::vector<int>::size_type i=0; i<coll.size(); ++i) {
coll[i] = fo(); // call function for function object
}
}
int main()
{
// create vector with 10 elements
std::vector<int> v(10);
// (re)initialize values with wrapped function
initialize<FunctionReturningIntWrapper<random_int> >(v);
// output elements
for (std::vector<int>::size_type i=0; i<v.size(); ++i) {
std::cout << "coll[" << i << "]: " << v[i] << std::endl;
}
}