The following code example is taken from the book
The C++ Standard Library - A Tutorial and Reference, 2nd Edition
by Nicolai M. Josuttis, Addison Wesley Longman, 2012
Copyright © 2012 by Pearson Education, Inc. and Nicolai M. Josuttis
#include <iostream>
#include <list>
#include <algorithm>
#include <iterator>
#include "print.hpp"
using namespace std;
class IntSequence {
private:
int value;
public:
// constructor
IntSequence (int initialValue)
: value(initialValue) {
}
// "function call"
int operator() () {
return value++;
}
};
int main()
{
list<int> coll;
IntSequence seq(1); // integral sequence starting with 1
// insert values from 1 to 4
// - pass function object by reference
// so that it will continue with 5
generate_n<back_insert_iterator<list<int>>,
int, IntSequence&>(back_inserter(coll), // start
4, // number of elements
seq); // generates values
PRINT_ELEMENTS(coll);
// insert values from 42 to 45
generate_n (back_inserter(coll), // start
4, // number of elements
IntSequence(42)); // generates values
PRINT_ELEMENTS(coll);
// continue with first sequence
// - pass function object by value
// so that it will continue with 5 again
generate_n (back_inserter(coll), // start
4, // number of elements
seq); // generates values
PRINT_ELEMENTS(coll);
// continue with first sequence again
generate_n (back_inserter(coll), // start
4, // number of elements
seq); // generates values
PRINT_ELEMENTS(coll);
}