尝试在循环中动态初始化 3 维向量时出现分段错误

Question

我正在创建一个名为 points_in_clusters 的向量>。目的是将 csv 文件的线（点）存储到 3D 矢量中。向量的第一个维度是簇号，其余的 (vector) 是属于相应簇的点集。因此，例如，在阅读文件后，我希望有一个这样的向量：

vector<vector<vector<string>>> points_in_clusters = 
{
{{"a","b","c"},{"q","w","e"}}, //points which belongs to cluster "0"
{{"f","k","l"} , {"a","b","l"},{"f","b","l"}} //belongs to cluster "1"
};

问题是我无法在循环中动态执行此操作，因为我收到此错误：分段错误（核心已转储）${command}

这是主要功能：

int main(int argc, char *argv[])
{
   
    char fileName[] =  "points.csv";
    int k = 2;
    /*****read_initial_clusters*****/
    vector<vector<vector<string>>> points_in_clusters;

    for(int numCluster = 0 ; numCluster < k ; ++numCluster){
        read_initial_clusters(k , fileName , step , numCluster  ,points_in_clusters);
    }

return 0

}

这里是 read_initial_clusters 函数：

void read_initial_clusters(int k , string fileName , int step , int numCluster  , vector<vector<vector<string>>>& points_in_clusters ){
    
    int numCommas = 0;
    
    string line;
    ifstream myfile(fileName,ios::in);

    vector<string> point;
    
    
    if(!myfile.is_open()){
        cout<<"Failed to open"<<endl;
        exit(0);
    }
    
    int start_line = numCluster * step;
    int end_line = start_line + step;
    

    int myShare = 0;
    int line_counter = 0; 

    while (getline(myfile, line))
    {
       
        if( myShare <= step)
        {
            if(start_line <= line_counter && line_counter < end_line)
            {
                myShare++;
                stringstream sline(line);
                string word;
                while (getline(sline , word , ','))
                {
                    point.push_back(word);
                    numCommas++;
                }
                
                **points_in_clusters[numCluster].push_back(point);**//------->Source of error
                point.clear();
                line_counter++;

            }
            else
            {
    
                line_counter++;

            }
         
        }
        else
        {
            
            myfile.close();
        }
            

    }//While
    
}

问题是，如果我首先用一些含糊不清的东西初始化我的 points_in_clusters（考虑到第一维的数量），那么“read_initial_clusters 函数”中的 push_back 会起作用正确但如果不正确，我会收到此段错误。另一方面，唯一事先确定的是我的第一个维度的数字，即簇号，其余的必须动态填充。

有什么办法可以解决这个问题吗？

Answer 1

你的vector是空的，改一下

for(int numCluster = 0 ; numCluster < k ; ++numCluster){
    read_initial_clusters(k , fileName , step , numCluster  ,points_in_clusters);
}

至此

for(int numCluster = 0 ; numCluster < k ; ++numCluster){
    points_in_clusters.push_back({});
    read_initial_clusters(k , fileName , step , numCluster  ,points_in_clusters);
}

看起来您正在正确处理其他维度，但您还需要在第一个维度上push_back。

尝试在循环中动态初始化 3 维向量时出现分段错误

Getting Segmentation fault while trying to initialise a 3 dimensional vector dynamically in a loop

c++

3d

vector

dynamic

segmentation-fault