map
#include <bits/stdc++.h> //map的基本操作如下
using namespace std;int main()
{// 构造函数map <string,int> dict;// 下标类型 存储的值的类型 // 插入数据的三种方式dict.insert(pair <string,int> ("apple",2));dict.insert(map <string, int> :: value_type("orange",3));dict["banana"] = 6;// 判断是否有元素if(dict.empty())cout<<"该字典无元素"<<endl;elsecout<<"该字典共有"<<dict.size()<<"个元素"<<endl;// 遍历map <string,int> :: iterator iter;for(iter = dict.begin();iter != dict.end();iter++){cout << iter->first << ends << iter->second << endl;}// 查找if((iter = dict.find("banana")) != dict.end()) // 返回一个迭代器指向键值为key的元素，如果没找到就返回end()cout << "已找到banana,其value为" << iter->second << "." << endl;elsecout << "未找到banana." << endl;if(dict.count("watermelon") == 0) // 返回键值等于key的元素的个数cout << "watermelon不存在" << endl;elsecout << "watermelon存在" << endl;pair <map<string,int> :: iterator, map<string,int> :: iterator> ret;ret = dict.equal_range("banana"); // 查找键值等于 key 的元素区间为[start,end)，指示范围的两个迭代器以 pair 返回cout << ret.first->first << ends << ret.first->second << endl;cout << ret.second->first << ends << ret.second->second << endl;iter = dict.lower_bound("boluo"); // 返回一个迭代器，指向键值>=key的第一个元素。cout << iter->first << endl;iter = dict.upper_bound("boluo"); // 返回一个迭代器，指向值键值>key的第一个元素。cout << iter->first << endl;return 0;
}
unordered_map
#include<bits/stdc++.h>
using namespace std; int main()
{unordered_map <string,int> dict; // 声明unordered_map对象// 插入数据的三种方式dict.insert(pair<string,int>("apple",2));dict.insert(unordered_map<string, int>::value_type("orange",3));dict["banana"] = 6;// 判断是否有元素if(dict.empty())cout<<"该字典无元素"<<endl;elsecout<<"该字典共有"<<dict.size()<<"个元素"<<endl;// 遍历unordered_map <string,int> :: iterator iter;for(iter = dict.begin();iter != dict.end();iter++)cout << iter->first << ends << iter->second << endl;// 查找if(dict.count("boluo") == 0)cout << "can't find boluo!" << endl;elsecout << "find boluo!" << endl;if((iter = dict.find("banana")) != dict.end())cout << "banana=" << iter->second << endl;elsecout << "can't find boluo!" << endl;return 0;
}
CSDN讲解
