binary_search a list
/* 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); // check existence of element with value 5 if (binary_search(coll.begin(), coll.end(), 5)) { cout << "5 is present" << endl; } else { cout << "5 is not present" << endl; } // check existence of element with value 42 if (binary_search(coll.begin(), coll.end(), 42)) { cout << "42 is present" << endl; } else { cout << "42 is not present" << endl; } } /* 1 2 3 4 5 6 7 8 9 5 is present 42 is not present */
1. | Illustrating the generic binary search algorithms | ||
2. | Use binary_search to locate a value in a vector |