overloading ostream issue

[AL88]

Hi I got this of a youtube video but I can't get it to compile, can anybody tell me what is wrong and teach me a bit about overloading the ostream operator? I think the problem is lines 32-36. thanks

#include<iostream>
#include<string>

struct Vector2
{
	float x, y;
	
	Vector2(float x, float y)
	: x(x), y(y) {}
	
	Vector2 Add(const Vector2& other) const
    {
		return Vector2(x + other.x, y + other.y);
	}
	
	Vector2 operator+(const Vector2& other) const
	{
		return Add(other);
	}
	
	Vector2 Multiply(const Vector2& other) const
    {
		return Vector2(x * other.x, y * other.y);
	}
	
	Vector2 operator*(const Vector2& other) const
	{
		return Multiply(other);
	}
};

std::ostream& operator<<(std::string& ostream, const Vector2 & other)
{
	stream << other.x << ", " << other.y;
	return stream;
}


int main()
{
	Vector2 position(4.0f, 4.0f);
    Vector2 speed(0.5f, 1.5f);
    Vector2 powerup(1.1f, 1.1f);
    
    Vector2 result1 = position.Add(speed.Multiply(powerup));
    Vector2 result2 = position + speed * powerup; 
    
    std::cout<<result2<<std::endl;

	return 0;
}

[jlb]

You're trying to overload an ostream& so your first parameter should be an ostream& not a std::string&

[AL88]

Thanks that helped a lot, now what should I replace stream with as that is producing the error "stream was not declared in this scope"?
Thanks.

[jlb]

What did you name the ostream& parameter? Maybe use that?

[AL88]

Thanks for your invaluable help, got it to compile :-)