CODEWITHSUNDEEP
c++pointersstruct
stressed_geek
stressed_geek

Reputation: 2176

How to use pointers to point to vector of a struct?

struct Edge;

struct Node {
    int id;
    vector<Edge> *edges;
};

struct Edge {
    int id;
    Node* vertex1;
    Node* vertex2;
};

int main(){
    vector<Edge> nodeEdgeList;
    Node* nodePtr = new Node;
    nodePtr->id = vertex;
    nodePtr->edges = nodeEdgeList;
}

I get the following compiler error due to the last line.

error: cannot convert 'std::vector<Edge, std::allocator<Edge> >' to 'std::vector<Edge, std::allocator<Edge> >*' in assignment

Upvotes: 0

Views: 1976

Answers (2)

EdChum
EdChum

Reputation: 393973

You Node class has a vector * as a member you are trying to set a non pointer to a pointer

The error message is pretty clear here error: cannot convert 'std::vector<Edge, std::allocator<Edge> >' to 'std::vector<Edge, std::allocator<Edge> >*' in assignment

so change to:

int main(){
    vector<Edge> *nodeEdgeList = new Vector<Edge>;
    Node* nodePtr = new Node;
    nodePtr->id = vertex;
    nodePtr->edges = nodeEdgeList;
}

or

int main(){
    vector<Edge> nodeEdgeList;
    Node* nodePtr = new Node;
    nodePtr->id = vertex;
    nodePtr->edges = &nodeEdgeList;
}

Upvotes: 3

dash1e
dash1e

Reputation: 7807

int main(){
    vector<Edge> nodeEdgeList;
    Node* nodePtr = new Node;
    nodePtr->id = vertex;
    nodePtr->edges = &nodeEdgeList; // <-- use & before
}

Upvotes: 2

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