28 map

标准库的map类型

include < map >

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

using namespace  std;

int main()
{
//插入到map容器内部的元素默认是按照key从小到大来排序。
//key类型一定要重载<运算符
map <string, int> mapTest;

mapTest["aaa"] = 100;
mapTest["eee"] = 500;
mapTest.insert(map<string, int>::value_type("bbb", 200));
mapTest.insert(pair<string,int>("ccc",300));
mapTest.insert(make_pair("ddd",400));

map<string, int>::iterator it;//const_iterator，则下面3000不能修改
it = mapTest.find("ccc");
if (it != mapTest.end())
{
it->second = 3000;

}

mapTest.erase("bbb");
//map<string, int>::const_iterator it;
it = mapTest.find("ccc");
if (it != mapTest.end())
{
mapTest.erase(it);
}
//map<string, int>::const_iterator it;
for (it = mapTest.begin(); it != mapTest.end(); ++it)
{
cout << it->first << " " << it->second << endl;
}

return 0;
}