Use fill_n function to replace all but two elements with 'hi' : fill_n « STL Algorithms Modifying sequence operations « C++ Tutorial

1. C++ Tutorial
2. STL Algorithms Modifying sequence operations
3. fill_n

/* 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.
 */


#include <iostream>
#include <vector>
#include <deque>
#include <list>
#include <set>
#include <map>
#include <string>
#include <algorithm>
#include <iterator>
#include <functional>
#include <numeric>

/* PRINT_ELEMENTS()
 * - prints optional C-string optcstr followed by
 * - all elements of the collection coll
 * - separated by spaces
 */
template <class T>
inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="")
{
    typename T::const_iterator pos;

    std::cout << optcstr;
    for (pos=coll.begin(); pos!=coll.end(); ++pos) {
        std::cout << *pos << ' ';
    }
    std::cout << std::endl;
}

/* INSERT_ELEMENTS (collection, first, last)
 * - fill values from first to last into the collection
 * - NOTE: NO half-open range
 */
template <class T>
inline void INSERT_ELEMENTS (T& coll, int first, int last)
{
    for (int i=first; i<=last; ++i) {
        coll.insert(coll.end(),i);
    }
}


using namespace std;

int main()
{
    // print ten times 7.7
    fill_n(ostream_iterator<float>(cout, " "), // beginning of destination
           10,                                 // count
           7.7);                               // new value
    cout << endl;

    list<string> coll;

    // insert "hello" nine times
    fill_n(back_inserter(coll),       // beginning of destination
           9,                         // count
           "hello");                  // new value

    // replace all but two elements with "hi"
    fill_n(coll.begin(),              // beginning of destination
           coll.size()-2,             // count
           "hi");                     // new value
    PRINT_ELEMENTS(coll,"coll: ");
}

7.7 7.7 7.7 7.7 7.7 7.7 7.7 7.7 7.7 7.7
coll: hi hi hi hi hi hi hi hello hello