How to create dll in c++ with undecorate export functions

Question

Whenever I create dll in c++ the exported functions get decorated. How can I get undecorated functions.

class Trying{
private:
    void xyz();
public:
    static __declspec(dllexport) int WriteUserData(int data);
    static __declspec(dllexport) string SomeFunction(string data);
}

I am exporting only the two public functions WriteUserData and SomeFunction. But on exporting I get decorated names like ?WriteUserData@@@@SB@@l Most posts mention about using extern "C" as extern "C"static __declspec(dllexport) int WriteUserData(int data);but they are using it in functions that are outside any function. I cannot place extern "C" before the functions inside the class as it gives error linkage specification is not allowed.