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How can i convert the date type of the object to another?

This is my code I wrote a comment under the mistake. I am not allowed to do it in another way it should be two classes and it should be done in this way. If someone can help me i would appreciate this
Thank u
using System;
using MathLibrary;
namespace MathLibraryApp
{
class Program
{
static void Main(string[] args)
{
Vector v = new Vector();
Vector v1 = new Vector(4, 8, 12);
Vector v2 = new Vector(8,16,24);
Vector[] vectors = { v1, v2 };
Console.WriteLine(v.Add(vectors));
}
}
}
using System;
namespace MathLibrary
{
public class PointVectorBase
{
public PointVectorBase(double x=0 , double y=0 , double z=0 )
{
this.X = x;this.Y = y;this.Z = z;
}
protected virtual PointVectorBase CalculateSum(params Vector[] addends)
{
for (int i = 0; i < addends.Length; i++)
{
this.X = this.X + addends[i].X;
this.Y = this.Y + addends[i].Y;
this.Z = this.Z + addends[i].Z;
}
return this;
}
}
public class Vector : PointVectorBase
{
public Vector(double x = 0, double y = 0, double z = 0) : base(x, y, z){ }
public Vector Add(params Vector[] addends)
{
return this.CalculateSum(addends) ;
//Cannot implicitly convert type MathLibrary.PointVectorBase to MathLibrary.Vector. An explicit conversion exists (are you missing a cast?)
}
}
}

You can either cast the result like this:
public Vector Add(params Vector[] addends)
{
return this.CalculateSum(addends) As Vector;
}
This is dangerous though. Not all base vectors are vectors so you could have a null return. Same way as an animal is not always a cat in the public class cat: animal example.
Creating the implicit conversion is safer, though not always possible: https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/operators/user-defined-conversion-operators

Your method CalculateSum returns value type PointVectorBase. Method Add in Vector class should return Vector.
Due to inheritance you can cast result of a CalculateSum to a Vector so it would be return this.CalculateSum(addends) as Vector;

In this case I wouldn't go for inheritance. You are only extending the base class with methods.
The problem on your CalculateSum is that you're returning this as a result. Which is a strange pattern. Either go for a void method which alters the current instance or return a new instance (so leave the current instance unmodified). I would go for the latter.
If your question is about inheritance, this is not a good example you gave.
But if you want an other way:
In your example I would go for extension methods. Also this is a nice case to use structs. By writing extension methods, you can extend the Vector3 with extra methods..
using System;
namespace MathLibrary
{
public struct Vector3
{
public double X;
public double Y;
public double Z;
public Vector3(double x=0 , double y=0 , double z=0 )
{
this.X = x;
this.Y = y;
this.Z = z;
}
public Vector3 CalculateSum(params Vector3[] addends)
{
var result = new Vector3();
for (int i = 0; i < addends.Length; i++)
{
result.X = result.X + addends[i].X;
result.Y = result.Y + addends[i].Y;
result.Z = result.Z + addends[i].Z;
}
return result;
}
}
public static class VectorExtensions
{
public static Vector3 Add(this Vector3 vector, params Vector3[] addends)
{
return vector.CalculateSum(addends);
// the add should actually add to the current vector,
// which makes it less readable.. calculate sum and add is almost the same.
return vector.CalculateSum(
new Vector3 [] { vector }
.Concat(addends)
.ToArray() );
}
}
}
The more your code has a functional approach the less strange things will happen.

overloading operator c# Vector

So, I am trying to override the "-" operator in c# to be able to subtract 2 vectors, but my class cannot implement Vector.
namespace Vectors
{
class VectorUtilv
{
private Point _p;
private Point _p2;
private Vector _v;
public Vector V
{
get { return _v; }
set { _v = value; }
}
public Point AddVector(Vector v)
{
_p.X = (_p.X + v.X);
_p2.Y = (_p.Y + v.Y);
return _p2;
}
// This is where I am trying to override but I cant add the v.X or
// the v.Y because it is not a vector. If i cast it as a vector the
// override doesn't work.
//////////////////////////////////////////////////////////////////
public static VectorUtilv operator -(Vector a, Vector b)
{
Vector v = new Vector();
v.X = a.X - b.X;
v.Y = a.Y - b.Y;
return v;
}
}
}
Any idea how I can remedy this issue?

Because you are Trying to define Operator for Class. At least one of its Parameters should be used in Operator with Type of your Class. for example you cant have class Car and define Operator witch only Gets int.
You can't override the operator for existing classes.only your own classes.
If you cant Modify Vector Class then you should declare your own class named Vector. or use the Type of your class for operator.
so you can have
class VectorUtilv
{
private Point _p;
private Point _p2;
private Vector _v;
public static VectorUtilv operator -(VectorUtilv a, VectorUtilv b)
{
//...
}
}
or
class Vecotr
{
private Point _p;
private Point _p2;
private Vector _v;
public static Vecotr operator -(Vecotr a, Vecotr b)
{
//...
}
}
But if you use solution 2. then you need to use qualifiers when using Vector.
System.Windows.Vector // is in Windows assembly
Vector // is your class

You can only override an operator in its own class.
Move all of that code to the Vector class.

In your vector class, override the '-' operator in it
public class Vector
{
public int X { get; set; }
public int Y { get; set; }
public static Vector operator -(Vector a, Vector b)
{
Vector v = new Vector();
v.X = a.X - b.X;
v.Y = a.Y - b.Y;
return v;
}
}
Then, you can uses it like that
Vector v1 = new Vector { X = 5, Y = 9};
Vector v2 = new Vector { X = 3, Y = 4 };
Vector vr = v1 - v2;
Console.WriteLine("Resultant Vector X: {0} & Y:{1}", vr.X, vr.Y);
I hope it will help you.

Thanks for the great responses. I wish I would I have checked before I figured it out. Would have saved me lots of time. I ended up doing pretty much exactly as you all said. Here is what I have.
public static VectorUtil operator -(VectorUtil aHeroPoint, VectorUtil bEnemyPoint) {
VectorUtil v = new VectorUtil();
v.Vec = new Vector(( aHeroPoint._p.X - bEnemyPoint._p.X),( aHeroPoint._p.Y - bEnemyPoint._p.Y));
return v;
}

Using Generics to Multiply Integers

I have a class called GenericItem (first time using generics), suppose i wanted to multiply two items if they were of the type integer, as you can see I am trying it in the method returnCounterMultiply, but it does not allow me to multiply them although i am trying to convert them and also checking if they are of type integer.
namespace Components
{
public class GenericItem<T>
{
private T data;
private T counter;
public T Data
{
get { return data; }
set { data = value; }
}
public GenericItem(){}
public GenericItem(T _data)
{
data = _data;
}
public T returnCounterMultiply(T value)
{
int c = 0;
int d = 0;
if (counter.GetType() == typeof(int) && value.GetType() == typeof(int))
{
//cant multiply two of type T, why if i am converting to int?.
return (T)Convert.ChangeType(counter, typeof(Int32)) * (T)Convert.ChangeType(value, typeof(Int32));
}
return value;
}
}
}
I would appreciate some explanation on this as this is the first time I am working on it (this is just a sample class for understanding this GENERICS INTRO and this GENERICS CLASSES, but still having trouble understanding it.

I don't see what your trying to achieve, but if you have to do it I think you have to use an interface:
public interface IMultiplyable<T>
{
T Multiply(T x);
}
public class Int : IMultiplyable<Int>
{
private int _data { get; set; }
public Int(int data)
{
_data = data;
}
public Int Multiply(Int x)
{
return new Int(_data * x._data);
}
public override string ToString()
{
return _data.ToString();
}
}
public class GenericItem<T> where T : IMultiplyable<T>
{
private T data;
private T counter;
public T Data
{
get { return data; }
set { data = value; }
}
public GenericItem() { }
public GenericItem(T _data)
{
data = _data;
}
public T returnCounterMultiply(T value)
{
return Data.Multiply(value);
}
public override string ToString()
{
return Data.ToString();
}
}
Usage:
var a = new GenericItem<Int>(new Int(4));
MessageBox.Show(a.returnCounterMultiply(new Int(5)).ToString()); //20

In my opinion, using generics in this case is an overkill.
It would be nice that generic constraints support something like:
// T parameter is a type which overloads "+" operator...
where T : +
In your concrete case, I would argue you're going in the wrong way. Why don't you just create a class to implement such math operations where properties are typed as int?
Generics work better when T parameter (or any other parameter, of course...) can be constrained to receive types which have:
A public parameterless constructor.
Inherits or implements a class/interface
You need to constraint that T must be a class and not a struct...
When you go into a problem when using generics requires a type conversion, I believe you defeated the point of generics!

You can do something like this:
public class GenericItem<T>
{
private T data;
public T Data
{
get { return data; }
set { data = value; }
}
public GenericItem(){}
public GenericItem(T _data)
{
data = _data;
}
private Dictionary<Type, Delegate> operations =
new Dictionary<Type, Delegate>()
{
{ typeof(int), (Func<int, int, int>)((x, y) => x * y) },
{ typeof(string), (Func<string, string, string>)((x, y) => x + " " + y) },
};
public T returnCounterMultiply(T value)
{
if (operations.ContainsKey(typeof(T)))
{
var operation = (Func<T, T, T>)(operations[typeof(T)]);
return operation(data, value);
}
return value;
}
}
You just need to define, in the dictionary, one operation per valid types you're going to want to use and it just works without any converting of types (except to cast to the Func).
I had these test results:
var gii = new GenericItem<int>(42);
var xi = gii.returnCounterMultiply(2);
// xi == 84
var gis = new GenericItem<string>("Foo");
var xs = gis.returnCounterMultiply("Bar");
// xs == "Foo Bar"

Your problem has nothing to do with generics but with basic C# casting priority:
//cant multiply two of type T, why if i am converting to int?.
return
(T)Convert.ChangeType(counter, typeof(Int32))
*
(T)Convert.ChangeType(value,typeof(Int32));
You do not multiply int but T - and T being a generic type you can only use methods that are ddefined in your generics contraint, which you have none, so no multiply on it.
If you want to multiply int, then do so:
(T) (
((Int32)Convert.ChangeType(counter, typeof(Int32)))
*
((Int32)Convert.ChangeType(value,typeof(Int32)))
);
See the difference?
Basically in your code you deal with T in the multiplication, here I deal with Int32. And factually if T is a Int32 (as you tested before in the IF statement) you can just skip the convert and cast:
(T) (
((Int32)counter)
*
((Int32)value)
);
Now, generics are a bad example for maths as you can not use operations on generics - sadly. This is an abuse of the concept, but I take it was meant as a learning exercise and thus focused on that part on my answer.

I too tried this once and had to find out that there is no pretty way to do it with generics. You cannot do it as generic as in C++.
As an alternative, you may wrap your data types and use a common interface:
interface IMathOps
{
object Value { get; }
void Add(IMathOps other);
// other methods for substraction etc.
}
class IntWrapper : IMathOps
{
public int value;
public void Add(IMathOps other)
{
if(other is IntWrapper)
{
this.value += (int)other.Value;
}
}
public object Value { get { return this.value; } }
}
// class FloatWrapper : IMathOps ...

I think you should use where (generic type constraint). So it will give error at compile time if T is not int.
public T returnCounterMultiply(T value) where T : int
{
int c = 0;
int d = 0;
return c*d;
}

Converting object of a class to of another one

I have two classes which have are nearly equal except the data types stored in them. One class contains all double values while other contains all float values.
class DoubleClass
{
double X;
double Y;
double Z;
}
class FloatClass
{
float X;
float Y;
float Z;
}
Now I have a point of DoubleClass which I want to convert to FloatClass.
var doubleObject = new DoubleClass();
var convertedObject = (FloatClass)doubleObject; // TODO: This
One simple way is to make a method which creates a new FloatClass object, fills all values and return it. Is there any other efficient way to do this.

Use a conversion operator:
public static explicit operator FloatClass (DoubleClass c) {
FloatCass fc = new FloatClass();
fc.X = (float) c.X;
fc.Y = (float) c.Y;
fc.Z = (float) c.Z;
return fc;
}
And then just use it:
var convertedObject = (FloatClass) doubleObject;
Edit
I changed the operator to explicit instead of implicit since I was using a FloatClass cast in the example. I prefer to use explicit over implicit so it forces me to confirm what type the object will be converted to (to me it means less distraction errors + readability).
However, you can use implicit conversion and then you would just need to do:
var convertedObject = doubleObject;
Reference

Sounds like you could use generics here:
public class GenericClass<T>
{
T X { get; set; }
T Y { get; set; }
T Z { get; set; }
}
GenericClass<float> floatClass = new GenericClass<float>();
GenericClass<double> doubleClass = new GenericClass<double>();

You can use Conversion Operators to achieve this.
Fr example:
struct FloatClass
{
public FloatClass(DoubleClass dClass) {
//conversion...
}
...
public static explicit operator FloatClass(DoubleClass dClass)
{
FloatClassd = new FloatClass(dClass); // explicit conversion
return d;
}
}
var convertedObject = (FloatClass)doubleObject;

You could add an implicit type conversion operator:
public class DoubleClass
{
public double X;
public double Y;
public double Z;
public static implicit operator FloatClass(DoubleClass d)
{
return new FloatClass { X = (float)d.X, Y = (float)d.Y, Z = (float)d.Z };
}
}
Now this works:
DoubleClass doubleObject = new DoubleClass();
FloatClass convertedObject = doubleObject;

Add a class for thease extention methods :
public static class ExtensionMethods
{
public static T ToObject<T>(this Object fromObject)
{
return JsonConvert.DeserializeObject<T>(JsonConvert.SerializeObject(fromObject));
}
public static List<T> ToObjectList<T>(this Object fromObject)
{
return JsonConvert.DeserializeObject<List<T>>(JsonConvert.SerializeObject(fromObject));
}
}
Use :
using YourExtentionMethodNamespace;
Class2 obj2 = obj1.ToObject<Class2>();
List<Class2> lst2 = _db.Blogs.ToList().ToObjectList<Class2>();

The simplest way to do this is by using serializer. Use Newtonsoft JSON serializer which works best.
using Newtonsoft.Json;
private void Convert()
{
DoubleClass doubleClass = new DoubleClass {X = 123.123, Y = 321.321, Z = 111.111};
var serializedoubleClass = JsonConvert.SerializeObject(doubleClass);
var floatClass = JsonConvert.DeserializeObject(serializedoubleClass, typeof(FloatClass));
}

Best way for Convert
public static class Extention {
public static string ConvertObjectToJson(this object ob)
{
return JsonConvert.SerializeObject(ob);
}
}
For Usage
var doubleClass = new DoubleClass {
x = 10,
y = 20
};
var floatClass = JsonConvert.DeserializeObject<FloatClass>(doubleClass.ConvertObjectToJson());

Best way is Serialize object and again desalinize it

C# Abstract Class Operator Overload

I have an abstract class, Vector, which I would like to overload the operators +,-,*, etc.
I want any derived classes to be able to use these, and get an object back with the same type as the calling object.
I tried with generics, (as follows, in brief), but I couldn't find a legal way to do it:
public static T operator +<T>( T V1, T V2) where T : Vector
{
//some calculation
return new T(args);
}
I then tried to do it just using the base class:
public static Vector operator+(Vector V1, Vector V2)
{
if (V1.Dimension != V2.Dimension)
throw new VectorTypeException("Vector Dimensions Must Be Equal");
double[] ArgList = new double[V1.Dimension];
for (int i = 0; i < V1.Dimension; i++) { ArgList[i] = V1[i] + V2[i]; }
return (Vector)Activator.CreateInstance(V1.GetType(), new object[] { ArgList});
}
If this method is passed in two child objects, it should perform the operation on them, and return a new object of the same heritage.
The problem I ran into with this is that I cannot enforce that all such child classes must have a constructor with the appropriate signature, and I can't call the base constructor to make the object.
What are ways to either (a) Make either of these work, or (b) do this elegantly in another way?

You could declare instance-level abstract methods which your subclass can override:
public abstract class Vector
{
protected abstract Vector Add(Vector otherVector);
public static Vector operator +(Vector v1, Vector v2)
{
return v1.Add(v2);
}
}
public class SubVector : Vector
{
protected override Vector Add(Vector otherVector)
{
//do some SubVector addition
}
}
Might run into some issues especially with multiple subclasses (Will SubVector have to know how to add with SomeOtherSubVectorClass? What if you add ThirdVectorType class?) and perhaps handling null cases. Also, making sure that SubVector.Add behaves the same as SomeOtherSubVectorClass.Add when it comes to commutative operations.
EDIT: based on your other comments, you could so something like:
public class Vector2D : Vector
{
public double X { get; set; }
public double Y { get; set; }
protected override Vector Add(Vector otherVector)
{
Vector2D otherVector2D = otherVector as Vector2D;
if (otherVector2D != null)
return new Vector2D() { X = this.X + otherVector2D.X, Y = this.Y + otherVector2D.Y };
Vector3D otherVector3D = otherVector as Vector3D;
if (otherVector3D != null)
return new Vector3D() { X = this.X + otherVector3D.X, Y = this.Y + otherVector3D.Y, Z = otherVector3D.Z };
//handle other cases
}
}
public class Vector3D : Vector
{
public double X { get; set; }
public double Y { get; set; }
public double Z { get; set; }
protected override Vector Add(Vector otherVector)
{
Vector2D otherVector2D = otherVector as Vector2D;
if (otherVector2D != null)
return new Vector3D() { X = this.X + otherVector2D.X, Y = this.Y + otherVector2D.Y, Z = this.Z };
Vector3D otherVector3D = otherVector as Vector3D;
if (otherVector3D != null)
return new Vector3D() { X = this.X + otherVector3D.X, Y = this.Y + otherVector3D.Y, Z = this.Z + otherVector3D.Z };
//handle other cases
}
}
EDITx2:
Given your latest comment, perhaps your should just maintain an internal array/matrix and just do generic matrix math. Your subclasses can expose X/Y/Z property wrappers against the array indicies:
public class Vector
{
protected double[] Values;
public int Length { get { return Values.Length; } }
public static Vector operator +(Vector v1, Vector v2)
{
if (v1.Length != v2.Length)
{
throw new VectorTypeException("Vector Dimensions Must Be Equal");
}
else
{
//perform generic matrix addition/operation
double[] newValues = new double[v1.Length];
for (int i = 0; i < v1.Length; i++)
{
newValues[i] = v1.Values[i] + v2.Values[i];
}
//or use some factory/service to give you a Vector2D, Vector3D, or VectorND
return new Vector() { Values = newValues };
}
}
}
public class Vector2D : Vector
{
public double X
{
get { return Values[0]; }
set { Values[0] = value; }
}
public double Y
{
get { return Values[1]; }
set { Values[1] = value; }
}
}
public class Vector3D : Vector
{
public double X
{
get { return Values[0]; }
set { Values[0] = value; }
}
public double Y
{
get { return Values[1]; }
set { Values[1] = value; }
}
public double Z
{
get { return Values[2]; }
set { Values[2] = value; }
}
}
EDITx3: Based on your latest comment, I guess you could implement operator overloads on each subclass, do the shared logic in a static method (say in the base Vector class), and somewhere do a switch/case check to provide a specific subclass:
private static Vector Add(Vector v1, Vector v2)
{
if (v1.Length != v2.Length)
{
throw new VectorTypeException("Vector Dimensions Must Be Equal");
}
else
{
//perform generic matrix addition/operation
double[] newValues = new double[v1.Length];
for (int i = 0; i < v1.Length; i++)
{
newValues[i] = v1.Values[i] + v2.Values[i];
}
//or use some factory/service to give you a Vector2D, Vector3D, or VectorND
switch (newValues.Length)
{
case 1 :
return new Vector1D() { Values = newValues };
case 2 :
return new Vector2D() { Values = newValues };
case 3 :
return new Vector3D() { Values = newValues };
case 4 :
return new Vector4D() { Values = newValues };
//... and so on
default :
throw new DimensionOutOfRangeException("Do not support vectors greater than 10 dimensions");
//or you could just return the generic Vector which doesn't expose X,Y,Z values?
}
}
}
Then your subclasses would have:
public class Vector2D
{
public static Vector2D operator +(Vector2D v1, Vector2D v2)
{
return (Vector2D)Add(v1, v2);
}
}
public class Vector3D
{
public static Vector3D operator +(Vector3D v1, Vector3D v2)
{
return (Vector3D)Add(v1, v2);
}
}
Some duplication, but I don't see a way around it off the top of my head to allow the compiler to do this:
Vector3 v1 = new Vector3(2, 2, 2);
Vector3 v2 = new Vector3(1, 1, 1);
var v3 = v1 + v2; //Vector3(3, 3, 3);
Console.WriteLine(v3.X + ", " + v3.Y + ", " + v3.Z);
or for other dimensions:
Vector2 v1 = new Vector2(2, 2);
Vector2 v2 = new Vector2(1, 1);
var v3 = v1 + v2; //Vector2(3, 3, 3);
Console.WriteLine(v3.X + ", " + v3.Y); // no "Z" property to output!

What about having an abstract method called Add() that operator+ just acts as a wrapper for? ie, "return v1.Add(v2)". This would also enable you to define interfaces which non-Vector classes can constrain their code to, enabling to perform math-like operations (since generic code can't see/touch operators like +, -, etc for any type).
The only constructor you can code with in a generic method is the default (ie, parameter-less) constructor, which you have to specify in the generic constraints for the method/type.

Five years later I had the exact same problem, only I was calling them Ntuples, not vectors. Here is what I did:
using System;
using System.Collections.Generic;
public class Ntuple{
/*parent class
has an array of coordinates
coordinate-wise addition method
greater or less than in dictionary order
*/
public List<double> Coords = new List<double>();
public int Dimension;
public Ntuple(List<double> Input){
Coords=Input;
Dimension=Input.Count;
}//instance constructor
public Ntuple(){
}//empty constructor, because something with the + overload?
public static Ntuple operator +(Ntuple t1, Ntuple t2)
{
//if dimensions don't match, throw error
List<double> temp = new List<double>();
for (int i=0; i<t1.Dimension; i++){
temp.Add(t1.Coords[i]+t2.Coords[i]);
}
Ntuple sum = new Ntuple(temp);
return sum;
}//operator overload +
public static bool operator >(Ntuple one, Ntuple other){
//dictionary order
for (int i=0; i<one.Dimension; i++){
if (one.Coords[i]>other.Coords[i]) {return true;}
}
return false;
}
public static bool operator <(Ntuple one, Ntuple other){
//dictionary order
for (int i=0; i<one.Dimension; i++){
if (one.Coords[i]<other.Coords[i]) {return true;}
}
return false;
}
}//ntuple parent class
public class OrderedPair: Ntuple{
/*
has additional method PolarCoords, &c
*/
public OrderedPair(List<double> Coords) : base(Coords){}
//instance constructor
public OrderedPair(Ntuple toCopy){
this.Coords=toCopy.Coords;
this.Dimension=toCopy.Dimension;
}
}//orderedpair
public class TestProgram{
public static void Main(){
List<double> oneCoords=new List<double>(){1,2};
List<double> otherCoords= new List<double>(){2,3};
OrderedPair one = new OrderedPair(oneCoords);
OrderedPair another = new OrderedPair(otherCoords);
OrderedPair sum1 = new OrderedPair(one + another);
Console.WriteLine(one.Coords[0].ToString()+one.Coords[1].ToString());
Console.WriteLine(sum1.Coords[0].ToString()+sum1.Coords[1].ToString());
bool test = one > another;
Console.WriteLine(test);
bool test2 = one < another;
Console.WriteLine(test2);
}
}
}//namespace ntuples