Question

Is this code ambiguous or is it perfectly fine (approved by standards/has consistent behavior for any compilers in existence)?

struct SCustomData {
    int nCode;
    int nSum;
    int nIndex;
    SCustomData(int nCode, int nSum, int nIndex)
        : nCode(nCode)
        , nSum(nSum)
        , nIndex(nIndex)
    {}
};

edit:
yes, I am referring to the fact that the member variables have the same name with formal parameters of the constructor.

Answer 1

No, in this case there are no ambiguity, but consider following:

struct SCustomData {
//...
    void SetCode(int nCode)
    {
            //OOPS!!! Here we do nothing!
            //nCode = nCode;

            //This works but still error prone
            this->nCode = nCode;
    }
};

You should draw attention to one of existing coding styles. For instance General Naming Rule in Google C++ Coding Styles or read excellent book “C++ Coding Standards: 101 Rules, Guidelines, and Best Practices” by Herb Sutter and Andrei Alexandrescu.