Exercise "vec"

• Build a class, called "vec" (we reserve the name "vector" for n-dimensional vectors), to represent Eucledean 3D vectors.

Tasks:

1. Start with something like

   public class vec{
   	public double x,y,z; /* the three components of a vector */
   	/* your stuff goes here */
   }
   

2. Implement a couple of constructors,

   //constructors:
   public vec(){ x=y=z=0; }
   public vec(double x,double y,double z){ this.x=x; this.y=y; this.z=z; }
   

3. Overload mathematical operators,

   //operators:
   public static vec operator*(vec v, double c){return new vec(c*v.x,c*v.y,c*v.z);}
   public static vec operator*(double c, vec v){return v*c;}
   public static vec operator+(vec u, vec v){/*...*/}
   public static vec operator-(vec u){return new vec(-u.x,-u.y,-u.z)}
   public static vec operator-(vec u, vec v){/*...*/}
   

4. Make a "print" method for debugging,

   //methods:
   public void print(string s){Write(s);WriteLine($"{x} {y} {z}");}
   public void print(){this.print("");}
   

5. Implement methods for dot-product, vector-product, and norm. Something like

   public double dot(vec other) /* to be called as u.dot(v) */
   	{return this.x*other.x+this.y*other.y+this.z*other.z;}
   public static double dot(vec v,vec w) /* to be called as vec.dot(u,v) */
   	{return v.x*w.x+v.y*w.y+v.z*w.z;}
   

   You can also try this C# syntactic sugar,

   public double dot(vec other) => this.x*other.x+this.y*other.y+this.z*other.z;
   public static double dot(vec v,vec w) => v.x*w.x+v.y*w.y+v.z*w.z;
   

6. Make an "approx" method to compare two vec's with absolute precision "acc" and relative precision "eps". Something like

   static bool approx(double a,double b,double acc=1e-9,double eps=1e-9){
   	if(Abs(a-b)<acc)return true;
   	if(Abs(a-b)<(Abs(a)+Abs(b))*eps)return true;
   	return false;
   	}
   public bool approx(vec other){
   	if(!approx(this.x,other.x)return false;
   	if(!approx(this.y,other.y)return false;
   	if(!approx(this.z,other.z)return false;
   	return true;
   	}
   public static bool approx(vec u, vec v) => u.approx(v);
   

7. Override ToString method, something like

   public override string ToString(){ return $"{x} {y} {z}"; }
   	

8. Put your "vec" class in the file "vec.cs" and compile it into a library,

   vec.dll: vec.cs
   	mcs -target:library -out:vec.dll vec.cs
   

   Create a "main.cs" file with the "Main" function that illustrates your implementation and link it with "vec.dll" like this,

   main.exe: main.cs vec.dll
   	mcs -target:exe -out:main.exe -reference:vec.dll vec.cs
   

9. Run extensive tests of your implementation in the Main function (see [../matlib/complex/main.cs] for inspiration).