C++标准库（第2版）STL 源码

/* The following code example is taken from the book * "The C++ Standard Library - A Tutorial and Reference, 2nd Edition" * by Nicolai M. Josuttis, Addison-Wesley, 2012 * * (C) Copyright Nicolai M. Josuttis 2012. * 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 <iomanip> #include <map> #include <string> #include <algorithm> #include <cctype> using namespace std; // function object to compare strings // - allows you to set the comparison criterion at runtime // - allows you to compare case insensitive class RuntimeStringCmp { public: // constants for the comparison criterion enum cmp_mode {normal, nocase}; private: // actual comparison mode const cmp_mode mode; // auxiliary function to compare case insensitive static bool nocase_compare(char c1, char c2) { return toupper(c1) < toupper(c2); } public: // constructor: initializes the comparison criterion RuntimeStringCmp(cmp_mode m = normal) : mode(m) { } // the comparison bool operator()(const string& s1, const string& s2) const { if (mode == normal) { return s1 < s2; } else { return lexicographical_compare(s1.begin(), s1.end(), s2.begin(), s2.end(), nocase_compare); } } }; // container type: // - map with // - string keys // - string values // - the special comparison object type typedef map<string, string, RuntimeStringCmp> StringStringMap; // function that fills and prints such containers void fillAndPrint(StringStringMap& coll); int main() { // create a container with the default comparison criterion StringStringMap coll1; fillAndPrint(coll1); // create an object for case-insensitive comparisons RuntimeStringCmp ignorecase(RuntimeStringCmp::nocase); // create a container with the case-insensitive comparisons criterion StringStringMap coll2(ignorecase); fillAndPrint(coll2); } void fillAndPrint(StringStringMap& coll) { // insert elements in random order coll["Deutschland"] = "Germany"; coll["deutsch"] = "German"; coll["Haken"] = "snag"; coll["arbeiten"] = "work"; coll["Hund"] = "dog"; coll["gehen"] = "go"; coll["Unternehmen"] = "enterprise"; coll["unternehmen"] = "undertake"; coll["gehen"] = "walk"; coll["Bestatter"] = "undertaker"; // print elements cout.setf(ios::left, ios::adjustfield); for (const auto& elem : coll) { cout << setw(15) << elem.first << " " << elem.second << endl; } cout << endl; }