Using enum class type in switch causing errors

Question

I was hoping someone could help me out with an error I'm having using an enum class in a switch case. trying to use the traverse type to choose the path in the switch. Here is my code:

enum class TraverseType { PREORDER, INORDER, POSTORDER, BREADTHORDER };
private: 
    TraverseType traverseOrder;
public:
friend ostream& operator<<(ostream& out, const BTree& tree)
{
    TraverseType type = traverseOrder;//error
    switch (type)
    {
    case TraverseType::PREORDER:
    {

        break;
    }
    case TraverseType::INORDER:
    {

        break;
    }
    case TraverseType::POSTORDER:
    {

        break;
    }
    case TraverseType::BREADTHORDER:
    {

        break;
    }
    default:
    {
        break;
    }
    }
    return out;
}`

the error im getting is : Error C2440 'initializing': cannot convert from 'unknown' to 'TraverseType' and i have been trying to find a solution to this problem for hours now. If you need more code please let me know. Thank you for your help in advance

enum class TraverseType { PREORDER, INORDER, POSTORDER, BREADTHORDER }; <-- enum ends here. The code that follows is... not in anything and it's confusing the poor compiler. And me. What are you trying to do here? What's the goal? — user4581301
– user4581301, Commented Nov 22, 2018 at 4:54
@user4581301 it’s unfinished code. I’m just trying to get it to compile, however I’m trying to use the switch to select different ways to traverse a binary tree — D. Spani
– D. Spani, Commented Nov 22, 2018 at 4:56
Looks like you want enum class TraverseType { PREORDER, INORDER, POSTORDER, BREADTHORDER };class BTree { private:note the class BTree { stuffed in there. — user4581301
– user4581301, Commented Nov 22, 2018 at 5:03
@user4581301 do you mean i should move "template <calss P>" line because I tried that and it causes errors on its own. The answer I'm looking for is similar to the answer in stackoverflow.com/questions/9062082/… except i need the traverse type to be set in another function then used as a case in the switch — D. Spani
– D. Spani, Commented Nov 22, 2018 at 5:23
I think it would help to post the entire code - even better would be providing it on coliru.stacked-crooked.com or a similar online ide. — tangy
– tangy, Commented Nov 22, 2018 at 6:23

Raja Muthyala · Accepted Answer · 2018-11-22 06:49:54Z

0

Your friend function needs a reference to the class object to access its member - traverseOrder.

what is your class name? If it is BTree, then access the private member using its reference.

enum class TraverseType { PREORDER, INORDER, POSTORDER, BREADTHORDER };
private: 
    TraverseType traverseOrder;
public:
friend ostream& operator<<(ostream& out, const BTree& tree)
{
    TraverseType type = tree.traverseOrder;
    switch (type)

edited Nov 22, 2018 at 6:49

answered Nov 22, 2018 at 6:30

Raja Muthyala

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