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map容器：键值和实值是分开的，排序规则按照键值排序
#define _CRT_SECURE_NO_WARNINGS#include #include #include using namespace std;template void printMap(T &m){ for (map ::iterator it = m.begin(); it != m.end(); ++it){ cout << "key:" << it->first << " value:" << it->second << endl; }}//注意:map的排序规则，传入的参数不是pair类型，而是key类型struct mycompare{ bool operator()(int key1, int key2){ return key1 > key2; }};//1. map容器的使用void test01(){ //map是否支持随机访问？不支持随机访问，双向迭代器 //创建map容器 map mymap; //1. 第一种插入方式 mymap.insert(pair (3,"aaa")); //2. 第二种插入方式 mymap.insert(make_pair(6, "bbb")); //3. 第三种插入方式 mymap.insert(map ::value_type(2,"ccc")); //4. 第四种插入方式 mymap[4] = "ddd"; mymap[4] = "eee"; mymap.erase(2); printMap(mymap); //cout << "size:" << mymap.size() << endl; //如果使用[]号这种方式输出一个不存在的key的值，那么编译器会以指定key增加新的数据 //如果使用[]号方式插入一条key存在的数据，那么已有数据会被修改 //cout << mymap[100] << endl; //cout << "size:" << mymap.size() << endl;}//3. map查找操作/*find(key);//查找键key是否存在,若存在，返回该键的元素的迭代器；/若不存在，返回map.end();count(keyElem);//返回容器中key为keyElem的对组个数。对map来说，要么是0，要么是1。对multimap来说，值可能大于1。lower_bound(keyElem);//返回第一个key>=keyElem元素的迭代器。upper_bound(keyElem);//返回第一个key>keyElem元素的迭代器。equal_range(keyElem);//返回容器中key与keyElem相等的上下限的两个迭代器。*/void test02(){ map mymap; mymap.insert(make_pair(1, "aaa")); mymap.insert(make_pair(2, "bbb")); mymap.insert(make_pair(3, "ccc")); mymap.insert(make_pair(4, "ddd")); mymap.insert(make_pair(5, "eee")); map ::iterator it = mymap.find(30); if (it == mymap.end()){ cout << "查找失败!" << endl; } else{ cout << "Key:" << it->first << " Value:" << it->second << endl; } it = mymap.lower_bound(3); if (it == mymap.end()){ cout << "查找失败!" << endl; } else{ cout << "Key:" << it->first << " Value:" << it->second << endl; } it = mymap.upper_bound(3); if (it == mymap.end()){ cout << "查找失败!" << endl; } else{ cout << "Key:" << it->first << " Value:" << it->second << endl; } pair ::iterator, map ::iterator> ret = mymap.equal_range(3); if (ret.first != mymap.end()){ cout << "Key:" << ret.first->first << " Value:" << ret.first->second << endl; } if (ret.second != mymap.end()){ cout << "Key:" << ret.second->first << " Value:" << ret.second->second << endl; }}int main(){ //test01(); test02(); system("pause"); return EXIT_SUCCESS;}
map容器案例：员工分组案例
#define _CRT_SECURE_NO_WARNINGS#include #include #include #include #include using namespace std;//公司今天招聘了5个员工，5名员工进入公司之后，需要指派员工在那个部门工作//人员信息有: 姓名 年龄 电话 工资等组成//通过Multimap进行信息的插入 保存 显示//分部门显示员工信息 显示全部员工信息#define SALE_DEPATMENT 1 //销售部门#define DEVELOP_DEPATMENT 2 //研发部门#define FINACIAL_DEPATMENT 3 //财务部门class Woker{public: string mName; int mAge; int mSalary;};//创建员工void CreateWorkers(vector &vWorkers){ srand((unsigned int)time(NULL)); string nameSeed = "ABCDE"; for (int i = 0; i < 5;i ++){ Woker worker; worker.mName = "员工"; worker.mName += nameSeed[i]; worker.mAge = rand() % 30 + 30; worker.mSalary = rand() % 10000 + 10000; vWorkers.push_back(worker); }}//员工分组void WokerByGroup(vector &vWorkers, multimap &mWokers){ //遍历员工 for (vector ::iterator it = vWorkers.begin(); it != vWorkers.end(); ++it){ int departmentID = rand() % 3 + 1; //员工保存在分组之后容器中 mWokers.insert(make_pair(departmentID,*it)); }}void Group(multimap &mWokers, int depID){ multimap ::iterator it = mWokers.find(depID); int mcount = mWokers.count(depID); int index = 0; for (; it != mWokers.end() && index < mcount; ++it, ++index){ cout << "Name:" << it->second.mName << " Age:" << it->second.mAge << " Salary:" << it->second.mSalary << "美刀!" << endl; }}//打印各组员工信息void PrintWorkers(multimap &mWokers){ cout << "财务部门员工信息如下:" << endl; Group(mWokers, FINACIAL_DEPATMENT); cout << "研发部门员工信息如下:" << endl; Group(mWokers, DEVELOP_DEPATMENT); cout << "销售部门员工信息如下:" << endl; Group(mWokers, SALE_DEPATMENT);}int main(){ vector vWorkers;// 保存未分组的员工信息 multimap mWokers; //保存分组后的员工信息 CreateWorkers(vWorkers); WokerByGroup(vWorkers, mWokers); PrintWorkers(mWokers); system("pause"); return EXIT_SUCCESS;}
转载于:https://www.cnblogs.com/w-x-me/p/6796425.html