在比较类和对象的向量时，如何定义==运算符？

class Vector {
public:
    int x;
    int y;

    bool operator==(const Vector& other) const {
        return (x == other.x) && (y == other.y);
    }
};

class Vector {
public:
    int x;
    int y;

    friend bool operator==(const Vector& v1, const Vector& v2) {
        return (v1.x == v2.x) && (v1.y == v2.y);
    }
};

Vector v1 = {1, 2};
Vector v2 = {1, 2};

if (v1 == v2) {
    // 向量相等
} else {
    // 向量不相等
}