c++ - 运算符重载奇怪的结果

Question

这是我的类(class)

class Vector
{
public:
    Vector();
    Vector(float x, float y, float z);

    float x;
    float y;
    float z;

    Vector &operator+(const Vector &other) const;
    Vector &operator+=(const Vector &other);
    Vector &operator*(float n) const;
};

//op overloading functions impl
Vector &Vector::operator+(const Vector &other) const
{
    Vector result = *this;
    result.x += other.x;
    result.y += other.y;
    result.z += other.z;
    return result;
}

Vector &Vector::operator+=(const Vector &other) 
{
    this->x += other.x;
    this->y += other.y;
    this->z += other.z;
    return *this;
}

Vector &Vector::operator*(float n) const
{
    Vector result = *this;
    result.x *= n;
    result.y *= n;
    result.z *= n;
    return result;
}

尝试使用更复杂的方程式时，我得到的结果不正确。例如这个作品:

Vector vChange = velocity * time;
position += vChange;

虽然这不会:

position += velocity * time;

即它编译并运行，但将一些伪造的内容写入位置

这个也一样:

Vector& Reflect(const Vector& I, const Vector& N)
{
Vector v = I - 2 * Dot(N, I) * N;
}

你能告诉我我做错了什么吗？谢谢!

Answer 1

您正在返回对 operator* 中局部变量的引用。那是未定义的行为。改为按值返回:

Vector Vector::operator*(float n) const
{
    Vector result = *this;
    result.x *= n;
    result.y *= n;
    result.z *= n;
    return result;
}

同样适用于operator+。