数组指针段错误

Question

我不完全确定为什么我要为这段代码获得段错误。我有一个我想创建的对象指针数组。这是我的代码。

edge **test = new edge*[a]; //Edge is a predefined class I have created. a is a my size of my array. 
    graphCreate2(test, vertices, roads, a); //Note roads is an edge class I have already created also 

但是，当我尝试访问edge ** test的元素时，出现段错误。以下是我如何访问它。

void graphCreate2(edge **test, int vertices, edge *roads, int a) 
{ 
    for(int i = 0; i < a; i++) 
    { 
    e[i]->setEdgeSrc(roads[i].getEdgeSrc()); 
    e[i]->setEdgeDes(roads[i].getEdgeDes()); 
    e[i]->setLength(roads[i].getLength()); 
    cout << e[i]->getLength() << " " << e[i]->getEdgeSrc() << " " << endl; 
    } 
} 

可能有人知道我为什么会收到此段错误吗？我以为我分配内存，因为创建数组时调用构造函数谢谢！

Answer 1

构造函数是而不是要求每个edge。你只是创建指针数组，但他们指向垃圾。

您需要在循环中创建它们。

void graphCreate2(edge **test, int vertices, edge *roads, int a) 
{ 
    for(int i = 0; i < a; i++) 
    { 
    test[i] = new edge(); // create the edge 
    test[i]->setEdgeSrc(roads[i].getEdgeSrc()); 
    test[i]->setEdgeDes(roads[i].getEdgeDes()); 
    test[i]->setLength(roads[i].getLength()); 
    cout << test[i]->getLength() << " " << test[i]->getEdgeSrc() << " " << endl; 
    } 
}