C++ In a Nutshell

Name

generate function template — Fills a range with values returned from a function

Synopsis

template<typename FwdIter, typename Generator>
  void generate(FwdIter first, FwdIter last, Generator gen);

The generate function template fills the sequence [first, last) by assigning the result of calling gen( ) repeatedly.

Example

Example 13-2 shows a simple way to fill a sequence with successive integers.

Example 13-2. Using generate to fill a vector with integers

#include <algorithm>
#include <iostream>
#include <iterator>
#include <vector>
  
// Generate a series of objects, starting with "start".
template <typename T>
class series {
public:
  series(const T& start) : next(start) {}
  T operator(  )(  ) { return next++; }
private:
  T next;
};
  
int main(  )
{
  std::vector<int> v;
  v.resize(10);
  // Generate integers from 1 to 10.  std::generate(v.begin(  ), v.end(  ), series<int>(1));
  // Print the integers, one per line.
  std::copy(v.begin(  ), v.end(  ),
            std::ostream_iterator<int>(std::cout, "\n"));
}

Technical Notes

Complexity is linear: gen is called exactly last - first times.

See Also

fill function template, generate_n function template