Strange "Member function not viable" error in templated linear algebra vector class

Question

I'm implementing a templated vector class (not the data container, but the vector in the linear algebra sense), and I'm getting quite a few errors whenever I refer to `rhs` in my operator overloading. Also, my copy constructor doesn't seem to be working. ``` #ifndef __VecXd__VecXd__ #define __VecXd__VecXd__ #define ULL unsigned long long #include using namespace std; template class VecXd { public: explicit VecXd(ULL newDimension = 1) { dimension = newDimension; vector = new T[newDimension];} VecXd(const VecXd &rhs); VecXd& operator=(const VecXd &rhs); const VecXd operator+(const VecXd &rhs) const; VecXd& operator+=(const VecXd &rhs); friend ostream& operator<<(ostream &out, VecXd vec); friend istream& operator>>(istream &in, VecXd& vec); ~VecXd() { delete[] vector; } const ULL getDimension() { return dimension; } const T itemAtIndex(ULL index) { if(index >= dimension) throw 1; return vector[index]; } private: ULL dimension; T *vector; };…

Accepted Answer

To be able to call a function on a `const` object, you need to promise the compiler that the function will not modify the object. To do that, you mark the function with the keyword `const` after its argument list. For example, to make `getDimension` a `const` member function, you would change it to:

```
const ULL getDimension() const { return dimension; }
```

(Note that the `const` in the return type will have absolutely no effect, so you should get rid of it)

Strange "Member function not viable" error in templated linear algebra vector class

Solution

Problem