c++ map 增删查找四种基本操作

梦里梦外; 2021-11-10 14:28 551阅读 0赞

#include <iostream>
    #include <map>
    using namespace std;
    int main()
    {
        //definition the map of mymap
        std::map<char, int> mymap;
        // 使用{}赋值是从c++11开始的，因此编译器版本过低时会报错，如visual studio 2012
    /* map<int, string> ID_Name = {
                    { 2015, "Jim" },
                    { 2016, "Tom" },
                    { 2017, "Bob" } };
    */
        //three methods of  insert  data 
        mymap.insert(std::pair<char, int>('a', 100));    
        mymap.insert(std::pair<char, int>('z', 200));
        mymap.insert(pair<char, int>('b', 300));
        mymap['d']=400;
        mymap.insert(map<char,int>::value_type('f',500) );
        map<char,int>::iterator iter;
        // check 
        for(iter=mymap.begin();iter !=mymap.end() ;iter++)
               
               cout<<iter->first<<" "<<iter->second<<endl;
        //delete one element 
        iter =mymap.find('b');
        //mymap.erase(iter);
        int n= mymap.erase('b');
        cout<<"n:"<<n<<endl; //if delete b sucess ,return 1;else return 0
        
        for(iter=mymap.begin();iter !=mymap.end() ;iter++)
               cout<<iter->first<<" "<<iter->second<<endl;
        
        //change
        mymap['d']=4000;
        cout<<mymap['d']<<endl;
    
       // delete  all element
        mymap.erase( mymap.begin(), mymap.end() );  
      
        int nSize = mymap.size();
        cout<<nSize;
        return 0;
    }

参考：[https://www.cnblogs.com/fnlingnzb-learner/p/5833051.html][https_www.cnblogs.com_fnlingnzb-learner_p_5833051.html]

[https://blog.csdn.net/sevenjoin/article/details/81943864][https_blog.csdn.net_sevenjoin_article_details_81943864]

[https_www.cnblogs.com_fnlingnzb-learner_p_5833051.html]: https://www.cnblogs.com/fnlingnzb-learner/p/5833051.html
[https_blog.csdn.net_sevenjoin_article_details_81943864]: https://blog.csdn.net/sevenjoin/article/details/81943864