multimap的学习

来源：互联网发布：java工程师个人简历doc 编辑：程序博客网时间：2024/06/08 02:44
#include <map>#include <iostream>using namespace std;void test_multimap(){//构造 multimap 的测试数据  multimap<string, string> example;  example.insert(make_pair(string("A"), string("11")));  example.insert(make_pair(string("A"), string("22")));  example.insert(make_pair(string("A"), string("33")));  example.insert(make_pair(string("B"), string("44")));  example.insert(make_pair(string("B"), string("55")));  example.insert(make_pair(string("B"), string("66")));  example.insert(make_pair(string("C"), string("77")));  example.insert(make_pair(string("C"), string("88")));  example.insert(make_pair(string("C"), string("99")));  example.insert(make_pair(string("D"), string("000")));  example.insert(make_pair(string("D"), string("111")));  example.insert(make_pair(string("D"), string("222")));  example.insert(make_pair(string("F"), string("0000")));  example.insert(make_pair(string("F"), string("1111")));  example.insert(make_pair(string("F"), string("2222")));  example.insert(make_pair(string("F"), string("3333")));  std::string del_item("A");  multimap<string, string>::size_type count = example.erase(del_item);  std::string search_item = "C";  multimap<string, string>::iterator iter = example.find(search_item);  multimap<string, string>::size_type all = example.count(search_item);//采用指定数量遍历  for (multimap<string, string>::size_type cnt = 0; cnt < all; ++cnt, ++iter)  {    std::cout << iter->first << ":" << iter->second << endl;  }//采用一个指定范围的迭代器遍历  search_item = "B";  for (iter = example.lower_bound(search_item); iter != example.upper_bound(search_item); ++iter)  {    std::cout << iter->first << ":" << iter->second << endl;  }//使用成对迭代器来遍历元素  search_item = "D";  pair<multimap<string, string>::iterator, multimap<string, string>::iterator> pos;  for (pos = example.equal_range(search_item); pos.first != pos.second; ++pos.first)  {    std::cout << pos.first->first << ":" << pos.first->second << endl;  }//multimap 中删除元素  search_item = "F";  for (iter = example.begin(); iter != example.end();)  {    if (iter->second == "0000" || iter->second == "2222")    {      std::cout << "erase " << iter->first << ":" << iter->second << endl;      example.erase(iter++);    }    else    {      iter++;    }  }//输出所有元素  for (iter = example.begin(); iter != example.end(); ++iter)  {    std::cout << iter->first << ":" << iter->second << endl;  }//查看multimap 的帮助文件,没有看到 multimap::operator[] 的定义,所以应该不支持  //这个访问方式,就算支持,也不好定义其返回的值,比如 map 是这样定义的  //Type& operator[](const Key& _Key);multimap 不好定义}int main(int argc, char *argv[]){  test_multimap();  return 0;}
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