From:

Nick W <nickwniko89@googlemail.com>

Newsgroups:

comp.lang.c++.moderated

Date:

Wed, 22 Jul 2009 23:54:26 CST

Message-ID:

<b7175d48-8835-4e0a-8644-5364b78c9fc3@i6g2000yqj.googlegroups.com>

Thank you all very much for your replies. You've all been very

helpful!

I can't understand why C++ has such ambiguity between a function

declaration and initialisation in this way, and I will definitely keep

to the more familiar C syntax.

I especially enjoyed the criticism of the code, produced by the guy in

charge of our computing course. Though I will be interested in any

improvements, I believe we're pretty much constrained to using the

code given. For reference, here is the complete code:

class vector3d {

// Utility class for three-dimensional vector operations

public:

vector3d() {x=0.0; y=0.0; z=0.0;}

vector3d(double a, double b, double c=0.0) {x=a; y=b; z=c;}

vector3d(int a, int b, int c=0) {x=double(a); y=double(b); z=double

(c);}

bool operator==(const vector3d& v) { if ((x==v.x)&&(y==v.y)&&

(z==v.z)) return true; else return false; }

bool operator!=(const vector3d& v) { if ((x!=v.x)||(y!=v.y)||(z!

=v.z)) return true; else return false; }

vector3d operator+(const vector3d& v) { return vector3d(x+v.x, y

+v.y, z+v.z); }

vector3d operator-(const vector3d& v) { return vector3d(x-v.x, y-

v.y, z-v.z); }

vector3d& operator+=(const vector3d& v) { x+=v.x; y+=v.y; z+=v.z;

return *this; }

vector3d& operator-=(const vector3d& v) { x-=v.x; y-=v.y; z-=v.z;

return *this; }

vector3d operator^(const vector3d& v) { return vector3d(y*v.z-z*v.y,

z*v.x-x*v.z, x*v.y-y*v.x); }

double operator*(const vector3d& v) { return (x*v.x + y*v.y

+z*v.z); }

friend vector3d operator*(const vector3d& v, const double& a)

{ return vector3d(v.x*a, v.y*a, v.z*a); }

friend vector3d operator*(const double& a, const vector3d& v)

{ return vector3d(v.x*a, v.y*a, v.z*a); }

vector3d& operator*=(const double& a) { x*=a; y*=a; z*=a; return

*this; }

vector3d operator/(const double& a) { return vector3d(x/a, y/a, z/

a); }

vector3d& operator/=(const double& a) { x/=a; y/=a; z/=a; return

*this; }

double abs2() { return (x*x + y*y + z*z); }

double abs() { return sqrt(this->abs2()); }

vector3d norm() { double s(this->abs()); if (s==0) return *this;

else return vector3d(x/s, y/s, z/s); }

double x, y, z;

private:

};

Nick

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