C++ STL map和 unordered_map

#include<string>
#include<iostream>
#include<map>

using namespace std;

struct person
{
	string name;
	int age;

	person(string name, int age)
	{
		this->name = name;
		this->age = age;
	}

	bool operator < (const person& p) const
	{
		return this->age < p.age;
	}
};

map<person, int> m;

int main()
{
	person p1("Tom1", 20);
	person p2("Tom2", 22);
	person p3("Tom3", 22);
	person p4("Tom4", 23);
	person p5("Tom5", 24);

	m.insert(make_pair(p3, 100));
	m.insert(make_pair(p4, 100));
	m.insert(make_pair(p5, 100));
	m.insert(make_pair(p1, 100));
	m.insert(make_pair(p2, 100));

	for (map<person, int>::iterator iter = m.begin(); iter != m.end(); iter++)
	{
		cout << iter->first.name << "\t" << iter->first.age << endl;
	}

	return 0;
}

#include <iostream>
#include <unordered_map>

using namespace std;


struct Person
{
	string name;
	int age;

	Person(string name, int age)
	{
		this->name = name;
		this->age = age;
	}
	/*bool operator == (const Person& pera) const {
		return this->name==pera.name && this->age==pera.age;
	}*/
	
};

/* the object of hash function */
struct PersonHash
{
	//计算hash值
	size_t operator()(const Person& per) const {
		return hash<string>()(per.name) ^ hash<int>()(per.age);
	}
};

/* the object of compare */
struct PersonCmp
{
	bool operator()(const Person& pera, const Person& perb) const {
		return pera.name == perb.name && pera.age == perb.age;
	}
};

/* define the unordered_map type */
typedef unordered_map<Person, int, PersonHash, PersonCmp> umap;


int main()
{
	umap m;
	Person p1("Tom1", 20);
	Person p2("Tom2", 22);
	Person p3("Tom3", 22);
	Person p4("Tom4", 23);
	Person p5("Tom5", 24);
	m.insert(umap::value_type(p3, 100));
	m.insert(umap::value_type(p4, 100));
	m.insert(umap::value_type(p5, 100));
	m.insert(umap::value_type(p1, 100));
	m.insert(umap::value_type(p2, 100));

	/* 这里打印出来的顺序于插入顺序并不相同，确切的说是完全无序的 */
	for (umap::iterator iter = m.begin(); iter != m.end(); iter++)
	{
		cout << iter->first.name << "\t" << iter->first.age << endl;
	}
	return 0;
}