迭代向量c ++中的列表

时间:2013-10-29 10:39:42

标签: c++ list vector stl

我有这段代码:

#include <iostream>
#include <vector>
#include <list>

using namespace std;

class Graph {
    public:
        //Create graph with n nodes
        Graph(int size);
             ~Graph();

        //Initialize graph
        void InitializeGraphWithRandomNum();


    private:

        vector <list <int*> > *graph;

};


void Graph::InitializeGraphWithRandomNum() {
    //Here I want to iterate
    for (int i=0; i< graph->size(); i++) {
        std::list <int*>::iterator it;
        for (it = graph[i].begin(); it< graph[i].end();++it) {
                 ..........
            }

    }
}
这里有些不对劲。它说

  

'= =(((图*)这里)''运算符='不匹配 - &gt;图形::图形+((无符号整数)(((unsigned int)i)* 12u))) - &gt ; std :: vector&lt; _Tp,_Alloc&gt; ::以_Tp = std :: list开头,_Alloc = std :: allocator&gt ;, std :: vector&lt; _Tp,_Alloc&gt; :: iterator = __gnu_cxx :: __ normal_iterator *,std :: vector&gt; &gt;,typename std :: _ Vector_base&lt; _Tp,_Alloc&gt; :: _ Tp_alloc_type :: pointer = std :: list *'DejkstraAlg.cpp

谢谢 最好

4 个答案:

答案 0 :(得分:3)

graph是指向矢量的指针,而不是矢量。要么将其声明为向量,要么使用(*graph)[i].begin()

答案 1 :(得分:3)

更改为

void Graph::InitializeGraphWithRandomNum()
{
    typedef list<int*> int_list;
    typedef vector<int_list> int_list_vector;

    for (int_list_vector::iterator vectit = graph->begin(); vectit != graph->end(); ++vectit)
    {
        for (int_list::iterator listit = vectit->begin(); listit != vectit->end(); ++listit)
        {
            int* value = *listit;
        }
    }
}

或者更干净,如果您有C ++ 11(不包含在您的标签中,但可能对其他人有用):

void Graph::InitializeGraphWithRandomNum()
{
    for (auto vectit = graph->begin(); vectit != graph->end(); ++vectit)
    {
        for (auto listit = vectit->begin(); listit != vectit->end(); ++listit)
        {
            int* value = *listit;
        }
    }
}

如果你进入C ++ 11非成员的开始/结束,许多C ++(像我一样)都支持:

void Graph::InitializeGraphWithRandomNum()
{
    for (auto vectit = begin(*graph); vectit != end(*graph); ++vectit)
    {
        for (auto listit = begin(*vectit); listit != end(*vectit); ++listit)
        {
            int* value = *listit;
        }
    }
}

答案 2 :(得分:1)

graph是指向vector的指针,也是将迭代器与end()比较使用operator!=而不是operator<

 for (it = (*graph)[i].begin(); it != (*graph)[i].end(); ++it)
 //                                ^^^

最好写一下:

vector <list<int>> graph;

答案 3 :(得分:0)

错误导致状态网(您未显示),您尝试将值分配给列表的元素。我想你忘了*它有指向int的指针。 而不是

*it = value;

你必须写

**it = value;