c++ 遍历vector , set , map

桃扇骨 2021-11-10 13:52 468阅读 0赞

vector ，set ，和map 属于c++ 的三种容器；遍历三种容器的重要方式是创建iterator ,迭代器在这里扮演了类似指针的角色，用迭代器来指向要访问的索引的值。

1: map  类似于python里面的字典。

#include <map>  
      
    #include <string>  
      
    #include <iostream>  
      
    using namespace std;  
    int main()  
      
    {  
      
        map<int, string> mapStudent;  
      
        mapStudent.insert(pair<int, string>(1, "student_one"));  
      
        mapStudent.insert(pair<int, string>(2, "student_two"));  
      
        mapStudent.insert(pair<int, string>(3, "student_three"));  
    
        map<int,string>::iterator iter;//please attention the name of  map,not name mapstudent 
        for(iter = mapStudent.begin();iter!=mapStudent.end();iter++)
           cout<<iter->first<<' '<<iter->second<<endl;
        
    }

2：set 里面不能容纳相同的元素

#include <set>
    #include <iostream>
    using namespace std;
    int main() {
    	set<int> iset;
    	iset.insert(1);
    	iset.insert(2);
    	iset.insert(3);
    	iset.insert(3);
    	for (set<int>::iterator iter = iset.begin(); iter != iset.end(); ++iter)
    		cout << *iter << endl;
    	system("pause");
    }

3：vector ：

#include <iostream>  
    #include <string> 
    #include <vector> 
    #include <algorithm>
    using namespace std;
    int main(){
      
        vector<vector<int> >res={
       {-1, 0, 1},{2, -1, -4}};
        int count = res.size();
        cout<<count<<endl;
        
        for(int i=0;i<count;i++){
            int  sun_len=res[i].size();
            for(int j=0;j<sun_len;j++)
                cout<<res[i][j];
            cout<<endl;
    
        }
    
        return 0;
    }

#include <vector>
    #include <iostream>
    using namespace std; 
    int main() {
        vector<int> ivec;
        ivec.push_back(1);
        ivec.push_back(2);
        ivec.push_back(3);
        ivec.push_back(4);
        for(vector<int>::iterator iter = ivec.begin();iter != ivec.end(); ++iter)
            cout << *iter << endl;
    }

引用：[https://blog.csdn.net/leviopku/article/details/82804227][https_blog.csdn.net_leviopku_article_details_82804227]

[https_blog.csdn.net_leviopku_article_details_82804227]: https://blog.csdn.net/leviopku/article/details/82804227