Mega Code Archive
Use find to search an element in a container
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/* 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()
{
list<int> coll;
INSERT_ELEMENTS(coll,1,9);
PRINT_ELEMENTS(coll,"coll: ");
// find first element with value 4
list<int>::iterator pos1;
pos1 = find (coll.begin(), coll.end(), // range
4); // value
/* find second element with value 4
* - note: continue the search behind the first 4 (if any)
*/
list<int>::iterator pos2;
if (pos1 != coll.end()) {
pos2 = find (++pos1, coll.end(), // range
4); // value
}
/* print all elements from first to second 4 (both included)
* - note: now we need the position of the first 4 again (if any)
* - note: we have to pass the position behind the second 4 (if any)
*/
if (pos1!=coll.end() && pos2!=coll.end()) {
copy (--pos1, ++pos2,
ostream_iterator<int>(cout," "));
cout << endl;
}
}
coll: 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
4 5 6 7 8 9 1 2 3 4
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