map遍历删除特定项和删除遍历删除所有项

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

using namespace std;

int main(void)
{
    map<string, string> data;

    data["a"] = "aaa";
    data["b"] = "bbb";
    data["c"] = "ccc";
    data["d"] = "ddd";
    data["e"] = "eee";
    data["f"] = "fff";
    data["g"] = "ggg";

    for (map<string, string>::iterator iter = data.begin(); iter != data.end(); ++iter)
    {
        cout << iter->first << ", " << iter->second << endl;
    }
    cout << "----------------------------" << endl;
    for (map<string, string>::iterator iter = data.begin(); iter != data.end();)
    {
        cout << "execute key: " << iter->first << endl;
        if ("g" == iter->first)
        {
            // windows STL支持返回值返回指向下一个元素指针
            iter = data.erase(iter);
        }
        else
        {
            ++iter;
        }
    }
    cout << "----------------------------" << endl;
    for (map<string, string>::iterator iter = data.begin(); iter != data.end(); ++iter)
    {
        cout << iter->first << ", " << iter->second << endl;
    }
}

 

 

    for (map<string, string>::iterator iter = data.begin(); iter != data.end();)
    {
        cout << "execute key: " << iter->first << endl;
        if ("g" == iter->first)
        {
            // windows和g++ STL均支持i自增方式
            data.erase(iter++);
        }
        else
        {
            ++iter;
        }
    }

 

 

 

    for (map<string, string>::iterator iter = data.begin(); iter != data.end();)
    {
        cout << "execute key: " << iter->first << endl;
        if ("g" == iter->first)
        {
            // windows和g++ STL均支持临时变量的方式，此种方式等效于自增变量方式
            map<string, string>::iterator copy = iter;
            ++iter;
            data.erase(copy);
        }
        else
        {
            ++iter;
        }
    }