//Original Author - clement //Just providing a corrected version of his code, to demonstrate what I wanted him to change... #include #include using namespace std; const double pi = 3.14159; struct vec2 { // start from (0, 0) vec2(double, double); ~vec2(); double getLength() const; double getSquaredLength() const; double getAngle(vec2 const&) const; void setAngle(double); void operator+=(vec2 const&); void operator-=(vec2 const&); void operator*=(double); vec2 operator+(vec2 const&) const; vec2 operator-(vec2 const&) const; double operator*(vec2 const&) const; double x; double y; }; ostream& operator<<(ostream&, vec2 const&); int main() { vec2 a(3,3), b(2, 2), x(1, 0); cout << a.getAngle(x) << endl; a.setAngle(60.0); cout << a.getAngle(x) << endl; cout << a << endl; return 0; } vec2::vec2(double xp, double yp): x(xp), y(yp) {} vec2::~vec2() {} double vec2::getLength() const { return sqrt(pow(x, 2) + pow(y, 2)); } double vec2::getSquaredLength() const { return pow(x, 2) + pow(y, 2); } double vec2::getAngle(vec2 const& axe) const { vec2 b(0, 0); vec2 ab(b.x - x, b.y - y); vec2 cb(b.x - axe.x, b.y - axe.y); float dot = (ab.x * cb.x + ab.y * cb.y); float cross = (ab.x * cb.y - ab.y * cb.x); float alpha = atan2(cross, dot); return -floor(alpha * 180. / pi + 0.5); } void vec2::setAngle(double angle) { double radangle = pi * angle / 180.; double mag = this->getLength(); x = mag * cos(radangle); y = mag * sin(radangle); } void vec2::operator+=(vec2 const& v) { x += v.x; y += v.y; } void vec2::operator-=(vec2 const& v) { x -= v.x; y -= v.y; } void vec2::operator*=(double m) { x *= m; y *= m; } vec2 vec2::operator+(vec2 const& v) const { vec2 vc(v); vc += *this; return vc; } vec2 vec2::operator-(vec2 const& v) const { vec2 vc(*this); vc -= v; return vc; } double vec2::operator*(vec2 const& v) const { return x * v.x + y * v.y; } ostream& operator<<(ostream& f, vec2 const& v) { f << "(" << v.x << ", " << v.y << ")"; }

vec2 - double_version