C++/STL Algorithms Non modifying sequence operations/find first of

Use find_first_of function to search first occurrence of an element

<source lang="cpp">

/* 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.
*/

1. include <iostream>
2. include <vector>
3. include <deque>
4. include <list>
5. include <set>
6. include <map>
7. include <string>
8. include <algorithm>
9. include <iterator>
10. include <functional>
11. 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> coll;
   list<int> searchcoll;
   INSERT_ELEMENTS(coll,1,11);
   INSERT_ELEMENTS(searchcoll,3,5);
   PRINT_ELEMENTS(coll,      "coll:       ");
   PRINT_ELEMENTS(searchcoll,"searchcoll: ");
   // search first occurrence of an element of searchcoll in coll
   vector<int>::iterator pos;
   pos = find_first_of (coll.begin(), coll.end(),     // range
                        searchcoll.begin(),   // beginning of search set
                        searchcoll.end());    // end of search set
   cout << "first element of searchcoll in coll is element "
        << distance(coll.begin(),pos) + 1
        << endl;

} /* coll: 1 2 3 4 5 6 7 8 9 10 11 searchcoll: 3 4 5 first element of searchcoll in coll is element 3

*/        
 </source>

Use find_first_of function to search last occurrence of an element

<source lang="cpp">

/* 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.
*/

1. include <iostream>
2. include <vector>
3. include <deque>
4. include <list>
5. include <set>
6. include <map>
7. include <string>
8. include <algorithm>
9. include <iterator>
10. include <functional>
11. 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> coll;
   list<int> searchcoll;
   INSERT_ELEMENTS(coll,1,11);
   INSERT_ELEMENTS(searchcoll,3,5);
   PRINT_ELEMENTS(coll,      "coll:       ");
   PRINT_ELEMENTS(searchcoll,"searchcoll: ");
   // search last occurrence of an element of searchcoll in coll
   vector<int>::reverse_iterator rpos;
   rpos = find_first_of (coll.rbegin(), coll.rend(),  // range
                         searchcoll.begin(),  // beginning of search set
                         searchcoll.end());   // end of search set
   cout << "last element of searchcoll in coll is element "
        << distance(coll.begin(),rpos.base())
        << endl;

} /* coll: 1 2 3 4 5 6 7 8 9 10 11 searchcoll: 3 4 5 last element of searchcoll in coll is element 5

*/
       
 </source>