c++ 中的集合类

概述

list

/* * array.cpp * *  Created on: 2014-3-21 *      Author: Administrator */#include <iostream>#include <vector>#include <deque>#include <list>#include <cstdlib>using namespace std;// compare only integral part:bool mycomparison(double first, double second) {return (int(first) > int(second));}void displayList(std::list<double> first) {std::cout << "displayList:";for (std::list<double>::iterator it = first.begin(); it != first.end();++it)std::cout << ' ' << *it;std::cout << '\n';}int merge() {std::list<double> first, second;first.push_back(3.1);first.push_back(2.2);first.push_back(2.9);second.push_back(3.7);second.push_back(7.1);second.push_back(1.4);displayList(first);displayList(second);first.sort();second.sort();displayList(first);displayList(second);first.merge(second);displayList(first);displayList(second);// (second is now empty)second.push_back(2.1);first.merge(second,mycomparison); //2.1 1.4 2.2 2.9 3.1 3.7 7.1displayList(first);//参数要求明明是个模板类为什么传方法也可以呢first.sort(mycomparison);displayList(first);return 0;//displayList: 3.1 2.2 2.9//displayList: 3.7 7.1 1.4//displayList: 2.2 2.9 3.1//displayList: 1.4 3.7 7.1//displayList: 1.4 2.2 2.9 3.1 3.7 7.1   结果是排序的//displayList://displayList: 1.4 2.2 2.9 2.1 3.1 3.7 7.1 结果是没排序的}void push() {list<int> list1(2, 1);cout << list1.size() << endl;list1.insert(list1.begin(), 10);list1.push_back(2);list1.push_back(3);list1.push_back(4);for (list<int>::iterator iter = list1.begin(); iter != list1.end();iter++) {cout << *iter << endl;}cout << list1.size() << endl;cout << list1.max_size() << endl;}int assign() //分配新的内容到列表容器，取代它的当前内容，并相应地修改其大小。{std::list<int> first;std::list<int> second;first.assign(7, 100); // 7 ints with value 100second.assign(first.begin(), first.end()); // a copy of firstint myints[] = { 1776, 7, 4 };first.assign(myints, myints + 3); // assigning from arraystd::cout << "Size of first: " << int(first.size()) << '\n';std::cout << "Size of second: " << int(second.size()) << '\n';return 0;}int splice ()// 拼接；{  std::list<int> mylist1, mylist2;  std::list<int>::iterator it;  // set some initial values:  for (int i=1; i<=4; ++i)     mylist1.push_back(i);      // mylist1: 1 2 3 4  for (int i=1; i<=3; ++i)     mylist2.push_back(i*10);   // mylist2: 10 20 30  it = mylist1.begin();  ++it;                         // points to 2  mylist1.splice (it, mylist2); // mylist1: 1 10 20 30 2 3 4                                // mylist2 (empty)                                // "it" still points to 2 (the 5th element)  mylist2.splice (mylist2.begin(),mylist1, it);                                // mylist1: 1 10 20 30 3 4                                // mylist2: 2                                // "it" is now invalid.  it = mylist1.begin();  std::advance(it,3);           // "it" points now to 30  mylist1.splice ( mylist1.begin(), mylist1, it, mylist1.end());                                // mylist1: 30 3 4 1 10 20  std::cout << "mylist1 contains:";  for (it=mylist1.begin(); it!=mylist1.end(); ++it)    std::cout << ' ' << *it;  std::cout << '\n';  std::cout << "mylist2 contains:";  for (it=mylist2.begin(); it!=mylist2.end(); ++it)    std::cout << ' ' << *it;  std::cout << '\n';  return 0;}int main_list() {//push();//merge();//assign();splice();return 0;}

set

/* * set.cpp * *  Created on: 2014-3-22 *      Author: Administrator */// set::insert (C++98)#include <iostream>#include <set>void displaySet(std::set<int> myset) {std::cout << "myset contains:";for (std::set<int>::iterator it = myset.begin(); it != myset.end(); ++it)std::cout << ' ' << *it;std::cout << '\n';}int get_allocator() {std::set<int> myset;int * p;unsigned int i;// allocate an array of 5 elements using myset's allocator://get_allocator 实际返回的是 class allocatorp = myset.get_allocator().allocate(5);// assign some values to arrayfor (i = 0; i < 5; i++)p[i] = (i + 1) * 10;std::cout << "The allocated array contains:";for (i = 0; i < 5; i++)std::cout << ' ' << p[i];std::cout << '\n';displaySet(myset);myset.get_allocator().deallocate(p, 5);displaySet(myset);return 0;}void insert() {std::set<int> myset;std::set<int>::iterator it;std::pair<std::set<int>::iterator, bool> ret;// set some initial values:for (int i = 1; i <= 5; ++i)myset.insert(i * 10); // set: 10 20 30 40 50ret = myset.insert(20); // no new element insertedif (ret.second == false)it = ret.first; // "it" now points to element 20myset.insert(it, 25); // max efficiency insertingmyset.insert(it, 24); // max efficiency insertingmyset.insert(it, 26); // no max efficiency insertingint myints[] = { 5, 10, 15 }; // 10 already in set, not insertedmyset.insert(myints, myints + 3);displaySet(myset);}int key_comp() {std::set<int> myset;int highest;std::set<int>::key_compare mycomp = myset.key_comp();for (int i = 0; i <= 5; i++)myset.insert(i * 10);std::cout << "myset contains:";highest = *myset.rbegin();std::cout << highest << std::endl;std::set<int>::iterator it = myset.begin();do {std::cout << ' ' << *it;} while (mycomp(*(++it), highest));//myset.key_comp() 通过的是_Compare，_Compare是 struct less 的别名，less重载了（）操作符//方法内部因没有访问内部的私有成员，所有不必用友元的方式，//总之就是比较大小，参数1<参数2返回真//  typedef _Compare key_compare;//  typename _Compare = std::less<_Key>,//  struct less : public binary_function<_Tp, _Tp, bool>//    {//      bool//      operator()(const _Tp& __x, const _Tp& __y) const//      { return __x < __y; }//    };std::cout << '\n';return 0;}int main_set() {//insert();//key_comp();get_allocator();return 0;}

map

/* * map.cpp * *  Created on: 2014-3-22 *      Author: Administrator */#include <iostream>#include <map>bool fncomp (char lhs, char rhs) {return lhs<rhs;}struct classcomp {  bool operator() (const char& lhs, const char& rhs) const  {return lhs<rhs;}};void map1() {std::map<char, int> first;first['a'] = 10;first['b'] = 30;first['c'] = 50;first['d'] = 70;std::map<char, int> second(first.begin(), first.end());std::map<char, int> third(second);std::map<char, int, classcomp> fourth; // class as Comparebool (*fn_pt)(char, char) = fncomp;std::map<char, int, bool (*)(char, char)> fifth(fn_pt); // function pointer as Compare}int main () {map1();  return 0;}