map是C++ STL Container中重要的一员，内部实现一般是平衡二叉树，用途非常广泛，编程示例如下：

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

using namespace std;

template<class T> 
void print_elements(T &elem){
	for(auto &p : elem) {
		cout << p.first << " : " << p.second << endl;
	}
}

int main(int argc, char **argv)
{
	map<string,string> m1;
	m1["mengguang"]="mengguang@gmail.com";
	print_elements(m1);
	cout << "is m1 empty? " << m1.empty() << endl;
	cout << "size of m1: " << m1.size() << endl;
	cout << "finding mengguang..." << endl;
	auto p=m1.find("mengguang");
	if( p != m1.end()) {
		cout << "got " << p->second << endl;	
	} else {
		cout << "not found." << endl;
	}
	m1.insert(make_pair("mengkang","mengkang@163.com"));
	m1.insert({"menghui","menghui@sina.com"});
	m1.erase("mengguang");
	print_elements(m1);
	m1.clear();
	cout << "is m1 empty? " << m1.empty() << endl;
	cout << "size of m1: " << m1.size() << endl;
	cout << m1["non_exists"] << endl;
	print_elements(m1);
	return 0;
}

参考资料：

http://www.cplusplus.com/reference/map/map/