Use transform to negate all elements in a container : transform « STL Algorithms Modifying sequence operations « C++ Tutorial






/* 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()
{
    vector<int> coll1;
    list<int> coll2;

    INSERT_ELEMENTS(coll1,1,9);
    PRINT_ELEMENTS(coll1,"coll1:   ");

    // negate all elements in coll1
    transform (coll1.begin(), coll1.end(),      // source range
               coll1.begin(),                   // destination range
               negate<int>());                  // operation
    PRINT_ELEMENTS(coll1,"negated: ");
}
coll1:   1 2 3 4 5 6 7 8 9
negated: -1 -2 -3 -4 -5 -6 -7 -8 -9








24.23.transform
24.23.1.std::transform with predicate
24.23.2.Transform all elements into deque from set by multiplying 10
24.23.3.Use transform function to square all elements in an array
24.23.4.Use generic template function with transform
24.23.5.Use transform to negate all elements in a container
24.23.6.Use transform to transform elements in one container into another container with ten times their value
24.23.7.Use transform to print elements negatively and in reverse order
24.23.8.Use transform to square each element
24.23.9.Use transform to add each element traversed forward with each element traversed backward
24.23.10.Transform array to pair
24.23.11.Use transform to print differences of two corresponding elements
24.23.12.Transform algorithm and list of integers
24.23.13.Transform v, putting the result into a new sequence
24.23.14.multiplying the elements in v with those in v2