c++ STL "map"

最新推荐文章于 2025-06-04 00:17:33 发布

wwzhang0307

最新推荐文章于 2025-06-04 00:17:33 发布

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本文详细介绍了C++标准库中map容器的使用方法，包括不同方式的元素插入、元素查找及删除等操作，并通过示例代码展示了如何进行map的遍历。

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#include <iostream>
using namespace std;
#include "map";
#include "string";
//map的添加/遍历/删除
void main1()
{
    map<int, string> map1;
    //插入方法1
    map1.insert(pair<int, string>(1, "teacher1"));
    map1.insert(pair<int, string>(2, "teacher2"));
    //插入方法2
    map1.insert(make_pair(3, "teacher3"));
    map1.insert(make_pair(4, "teacher4"));
    //插入方法3
    map1.insert(map<int, string>::value_type(5, "tracher5"));
    //插入方法4
    map1[6] = "teacher6";

    //容器变量
    for (map<int, string>::iterator it = map1.begin(); it != map1.end(); it++)
    {
        cout << it->first << "\t" << it->second << endl;
    }
    cout << endl;

    //容器的删除
    while (!map1.empty())
    {
        map<int, string>::iterator it = map1.begin();
        cout << it->first << "\t" << it->second << endl;
        map1.erase(it);
    }

}
//使用pair判断插入结果是否成功  map1[4]="obj" 若4已存在，则会修改其值
void main2()
{
    map<int, string> map1;
    //插入方法1
    map1.insert(pair<int, string>(1, "teacher1"));


    //使用pair判断插入结果是否成功
    pair<map<int, string>::iterator, bool> pair1 = map1.insert(pair<int, string>(1, "teacher11"));
    if (pair1.second == true)
    {
        cout << pair1.first->first << "\t" << pair1.first->second << endl;
    }
    else
    {
        cout << "(1, \"teacher11\")插入失败\n";
    }

    map1.insert(pair<int, string>(2, "teacher2"));
    //插入方法2
    map1.insert(make_pair(3, "teacher3"));
    map1.insert(make_pair(4, "teacher4"));
    //插入方法3
    map1.insert(map<int, string>::value_type(5, "tracher5"));
    //插入方法4
    map1[6] = "teacher6";

    //容器变量
    for (map<int, string>::iterator it = map1.begin(); it != map1.end(); it++)
    {
        cout << it->first << "\t" << it->second << endl;
    }
}
//map的查找
void main3()
{
    map<int, string> map1;
    //插入方法1
    map1.insert(pair<int, string>(1, "teacher1"));
    map1.insert(pair<int, string>(2, "teacher2"));
    //插入方法2
    map1.insert(make_pair(3, "teacher3"));
    map1.insert(make_pair(4, "teacher4"));
    //插入方法3
    map1.insert(map<int, string>::value_type(5, "tracher5"));
    //插入方法4
    map1[6] = "teacher6";

    //map的查找 find
    map<int, string>::iterator it = map1.find(5);
    if (it == map1.end())
    {
        cout << "key:5 未找到" << endl;
    }
    else
    {
        cout << it->first << "\t" << it->second << endl;
    }
    map<int, string>::iterator it1 = map1.find(7);
    if (it1 == map1.end())
    {
        cout << "key:7 未找到" << endl;
    }
    else
    {
        cout << it1->first << "\t" << it1->second << endl;
    }
    pair<map<int, string>::iterator, map<int, string>::iterator> pair1 = map1.equal_range(6);
    if (pair1.first == map1.end())
    {
        cout << "key>=6 未找到" << endl;
    }
    else
    {
        cout << pair1.first->first << "\t" << pair1.first->second << endl;
    }
    if (pair1.second == map1.end())
    {
        cout << "key>6 未找到" << endl;
    }
    else
    {
        cout << pair1.second->first << "\t" << pair1.second->second << endl;
    }
}

int main()
{
    //main1();
    //main2();
    main3();
    system("pause");
    return 0;
}