C++——STL(无序容器)
作者:互联网
无序容器
底层实现结构:哈希表 冲突解决方法为链地址法 快速查找(使用哈希函数)
名称 | 备注 |
---|---|
unordered_map | 键值不相等;不可重复;无序; |
unordered_multimap | 可重复; |
unordered_set | 键值相等;不可重复;有序;不可修改; |
unordered_multiset | 可重复; |
代码
(unordered_map)
#include<iostream>
#include<unordered_map>
#include<string>
using namespace std;
int main() {
//声明
unordered_map<string, string> umap;
unordered_map<string, string> umap{
{"Python教程","http://c.biancheng.net/python/"},
{"Java教程","http://c.biancheng.net/java/"},
{"Linux教程","http://c.biancheng.net/linux/"} };
unordered_map<string, string> umap2(umap);
unordered_map<string, string> umap2(++umap.begin(), umap.end());
//遍历
for (auto iter = umap.begin(); iter != umap.end(); iter++)
cout << iter->first << " " << iter->second << endl;
//查找
auto iter = umap.find("Python教程");
int count = umap.count("Python教程");
//插入
umap.insert(make_pair("STL教程", "http://c.biancheng.net/stl/"));//返回 pair<unordered_map<string,string>::iterator,bool>
umap.insert(++umap2.begin(), umap2.end());
umap.insert(++umap.begin(), { "Python教程","http://c.biancheng.net/python/" });
umap.insert({ {"STL教程","http://c.biancheng.net/stl/"},
{"Python教程","http://c.biancheng.net/python/"},
{"Java教程","http://c.biancheng.net/java/"} });
umap.emplace("STL教程", "http://c.biancheng.net/stl/");//返回 pair<unordered_map<string,string>::iterator,bool>
umap.emplace_hint(umap.begin(),"STL教程", "http://c.biancheng.net/stl/");//返回 unordered_map<string,string>::iterator
//删除
umap.erase(umap.end());
umap.erase("STL教程");
umap.erase(++umap.begin(), umap.end());
umap.clear();
//交换
umap.swap(umap2);
return 0;
}
(unordred_multimap)
- 没有[]定位指定key
- 没有at() 成员函数
- 头文件仍是引用 unordered_map
(unordered_set)
- 不再以键对方式存储
- 没有[]定位值
- 没有at()成员函数
- 不可修改
#include<iostream>
#include<unordered_set>
#include<string>
using namespace std;
int main() {
//声明
unordered_set<string> uset;
unordered_set<string> uset{
"http://c.biancheng.net/c/",
"http://c.biancheng.net/java/",
"http://c.biancheng.net/linux/" };
unordered_set<string> uset2(uset);
unordered_set<string> umap2(++uset.begin(), uset.end());
//删除
uset.erase(uset.end());
uset.erase("http://c.biancheng.net/c/");
uset.erase(++uset.begin(), uset.end());
return 0;
}
(unordered_multiset)
- 不再限定唯一值
- 头文件仍是引用 unordered_set
标签:http,STL,无序,C++,umap,uset,net,biancheng,unordered 来源: https://blog.csdn.net/Dedication_/article/details/116749946