在std :: vector中添加一个运算符<T>

Question

I am trying to add an operator to std::vector to identify when 2 vectors are approximately the same. How do I do it?

template<typename T> //only numeric types
class ImperciseVector: public std::vector<T> {
    public:
        ImperciseVector() {} //is this constructor needed?
        bool operator~ (const ImperciseVector& v) {
           T l1sq=0.0, l2sq=0.0, l3sq=0.0;

           if ((*this).size() != v.size() || (*this).size==0 || v.size()==0) return false; 
           for (int j = 0; j<(*this).size(); j++) {
               l1sq += (*this)[j]*(*this)[j];
               l2sq += v[j]*v[j];
               l3sq+= ((*this)[j]-v[j])*((*this)[j]-v[j]);
           }
           //some estimate such that length of their  their difference (relative to their size) is small enough
           if (l3sq/(l1sq*l2sq) <= 0.00001) return true; 
           return false;
        }
};

It does not work and does not even recognize when I write the operator what is ment. How to do it correctly or better?

Answer 1

operator~() is a unary operator. It's usage can only be ~iv , not iv1 ~ iv2 . It'd be better to simply write a member function called something like approx() or overload operator== in this case (in does make sense, right? Two ImpreciseVector s are equal if they're approximately equal?)

Side-note, don't have ImpreciseVector<T> inherit from vector<T> . Use composition instead.