琐碎的C ++向量中的神秘分割错误

Question

我想在这种方法中以某种迭代方式为向量p-> vertexlist赋值，并且当j = 3和i = 2时（在for迭代中）一直存在内存问题。

void py_tetgenio::set_facets(bp::list python_facets) {

this->numberoffacets = bp::len(python_facets);
this->facetlist = new tetgenio::facet[this->numberoffacets];
this->facetmarkerlist = new int[this->numberoffacets];

for (int i = 0; i < this->numberoffacets; i++) {
    //iterar por sobre la lista agregando cada uno de los
    //identificadores a cada uno de los facets
    bp::list facet = bp::extract<bp::list>(python_facets[i]);

    tetgenio::facet *f = &this->facetlist[i];
    f->numberofpolygons = 1;
    f->polygonlist = new tetgenio::polygon[f->numberofpolygons];
    f->numberofholes = 0;
    f->holelist = NULL;
    tetgenio::polygon *p = &f->polygonlist[i];

    //iterar por sobre la lista de los id de los nodos
    //almacenados en la lista que representa al facets

    p->numberofvertices = bp::len(facet);
    p->vertexlist = new int[p->numberofvertices];

    for (int j = 0; j < p->numberofvertices; j++) {
        int aux = bp::extract<int>(facet[j]);
        p->vertexlist[j] = aux; // SIGSEV:  Segmentation Fault!!! when j=3 
                                            // and i = 2
    }
    this->facetmarkerlist[i] = 1;
}
} //end set_facets

这是一个谜

Answer 1

注意：我们被告知i是2。

f->numberofpolygons = 1;
f->polygonlist = new tetgenio::polygon[f->numberofpolygons];

现在f->polygonlist指向大小为1的数组。

// Two irrelevant statements skipped
tetgenio::polygon *p = &f->polygonlist[i];

p现在是f->polygonlist中的第三个 （ i == 2 ）多边形的f->polygonlist 。 哦，但是