C++ Tutorial/STL Algorithms Modifying sequence operations/fill n

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Use fill_n function to insert "hello" nine times

/* 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
    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: hello hello hello hello hello hello hello hello hello

Use fill_n function to replace all but two elements with "hi"

/* 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

Use fill_n to Fill the three elements starting at offset position 3 with value -9

#include <algorithm>
#include <vector>
#include <iostream>
using namespace std;
int main ()
{
    vector <int> v (3);
    v.resize (6);
    // Fill the three elements starting at offset position 3 with value -9
    fill_n (v.begin () + 3, 3, -9);
    cout << "Contents of the vector are: " << endl;
    for (size_t nIndex = 0; nIndex < v.size (); ++ nIndex){
        cout << "Element [" << nIndex << "] = ";
        cout << v [nIndex] << endl;
    }
    return 0;
}

Use std::fill_n to fill the first five elements of chars with "A"

#include <iostream>
using std::cout;
using std::endl;
#include <algorithm> // algorithm definitions
#include <vector>    // vector class-template definition
#include <iterator>  // ostream_iterator
int main()
{
   std::vector< char > chars( 10 );
   std::ostream_iterator< char > output( cout, " " );
   std::fill( chars.begin(), chars.end(), "5" ); // fill chars with 5s
  // fill first five elements of chars with As
   std::fill_n( chars.begin(), 5, "A" );

   cout << "Vector chars after filling with 5s:\n";
   std::copy( chars.begin(), chars.end(), output );
   cout << endl;
   return 0;
}
Vector chars after filling with 5s:
A A A A A 5 5 5 5 5

Use the fill_n algorithms: Fill 3 more positions with Y"s

#include <iostream>
#include <cassert>
#include <algorithm>
#include <vector>
#include <string>
using namespace std;
int main()
{
  string s("Hello there");
  vector<char> vector1(s.begin(), s.end());

  fill_n(vector1.begin() + 5, 3, "Y");
  vector<char>::iterator pos;
  for (pos=vector1.begin(); pos!=vector1.end(); ++pos) {
        cout << *pos << " ";
  }

  return 0;
}
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