问c++ 2重载也有类似的转换，具体取决于操作符是成员函数还是全局函数。

EN

#include <algorithm>

class Vector {
public:
    Vector(int _elementsCount)
        : elementsCount(_elementsCount)
        , elements(new float[_elementsCount])
    {}
    ~Vector() {
        delete[] elements;
    }
    Vector(const Vector& rhs) {
        elementsCount = rhs.size();
        elements = new float[elementsCount];
        for (int i = 0; i < elementsCount; ++i)
            (*this)[i] = rhs[i];
    }

    float& operator [](int i) {
        return elements[i];
    }
    float operator [](int i) const {
        return const_cast<Vector&>(*this)[i];
    }
    int size() const {
        return elementsCount;
    }
    /*// Dot product
    float operator *(const Vector& v) {
        float res = 0;
        for (int i = 0; i < size(); ++i)
            res += (*this)[i] * v[i];
        return res;
    }*/
private:
    int elementsCount;
    float* elements;
};

// Multiplication by a scalar
Vector operator *(const Vector& v, float k) {
    Vector res(v.size());
    for (int i = 0; i < v.size(); ++i)
        res[i] = v[i] * k;
    return res;
}

// Dot product
float operator *(const Vector& v1, const Vector& v2) {
    float res = 0;
    for (int i = 0; i < std::min(v1.size(), v2.size()); ++i)
        res += v1[i] * v2[i];
    return res;
}

void main()
{
    Vector v(2);
    v * 3; // ambiguous
}