C# Math Design Logic 2

Thanks Vuples for being so helpful.

That looks fine to me, though I'd be careful using the double type if you need the numbers to be exact multiples of .01 as, internally, floating point numbers are seldom exact which can lead to cumulative round off errors.

Using the decimal type avoids this, though it is much slower than double and uses twice as much memory.

Incidentally, don't be frightened to use a simple for statement in C#. It's marginally faster than foreach and (usually) much faster than LINQ which has a lot of hidden overhead.

Vuples I think I am going to stick with logic below, I was trying to come up with another way to produce the logic below. And I am having a brain freeze, if you can come up with cool way to produce the logic below, that will give me the same output, then i will use it.


      
        public void CalculateExpression()
        {
            double y = 0.0;
            Dictionary coordinatesDictionary = new Dictionary();
            coordinatesDictionary.Clear();

            for (double x = 3.0; x <= 14.0; x = x + 0.01)
            {

                y = x + 3;
                coordinatesDictionary.Add(x, y);

            }

            string fn = @"c:\ArrayInfo20.csv";
            File.AppendAllLines(fn, coordinatesDictionary.Select(kvp => String.Format("{0:F2} | {1:F2}", kvp.Key, kvp.Value)));
            Process.Start(fn);
        }

If you're writing the results to a file, formatted to 2 dp, then you need to add an extra line:

i try to use the logic you use, the out is producing for the X values are wrong. your logic is not incrementing by 10 nano meters or .01.

Your output is producing



The output should produce this below instead for the equation below.

Dictionary coordinatesDictionary;
coordinatesDictionary = Enumerable.Range(10, 15).ToDictionary(i => i/100m, i => (i + 3)/100m); 

Wrong output
    X    |   Y
  -----------------
  10.01  | 10.03
  10.011  | 10.04
  10.012  | 10.05
  10.013| 10.06


Y = X + 3   

Correct Out using logic below

  Dictionary coordinatesDictionary = new Dictionary();

            double[] arrayRangeInfo = Enumerable.Range(0, 100).Select(i => (i * .01)).ToArray();
        
            foreach (int i in Enumerable.Range(10, 15))
            {
                foreach( var itemX in arrayRangeInfo)
                {
                    string xOutput = String.Format("{0:F2}", (i + itemX));

                    decimal X = Convert.ToDecimal(xOutput);
                    decimal Y = (X + 3);
                    coordinatesDictionary.Add(X, Y);
                }          
            }

      X    |   Y
  -----------------
  10.00  | 10.03
  10.01  | 10.04
  10.02  | 10.05
  10.03  | 10.06

As LINQ has a ToDictionary() method, you could condense all that into a couple of lines:

Dictionary coordinatesDictionary;
coordinatesDictionary = Enumerable.Range(1000, 501).ToDictionary(i => i/100m, i => (i + 3)/100m);

I will check out the link, but i came  up with some logic it works pretty well. review below.


            Dictionary coordinatesDictionary = new Dictionary();

            double[] arrayRangeInfo = Enumerable.Range(0, 100).Select(i => (i * .01)).ToArray();
        
            foreach (int i in Enumerable.Range(10, 15))
            {
                foreach( var itemX in arrayRangeInfo)
                {
                    string xOutput = String.Format("{0:F2}", (i + itemX));

                    decimal X = Convert.ToDecimal(xOutput);
                    decimal Y = (X + 3);
                    coordinatesDictionary.Add(X, Y);
                }          
            }

One of the shortcomings of the Enumerable.Range method is that it can only deal with integers.

To generate a range of decimals directly, with a step of .01, I'd check out my article on dealing with ranges of numbers in C#:

http://www.c-sharpcorner.com/uploadfile/b942f9/dealing-with-ranges-of-numbers-in-C-Sharp/

that will not do the job, when you step through the foreach below its incrementing by 1's. instead of .01, So the i below is increment by 1's instead of .01, I am basically increment by 10 nano meters.


            foreach (int i in Enumerable.Range(10 ,15))
            {
                decimal x = i / 1000m;

                string xOutput = String.Format("{0:F2} | {1:F2}", x, x + .03m);

                sw.WriteLine(xOutput);
            }

Hi vuples,


Below everying is iterating through the foreach by 1's how to iterate by 10 nano meters or .01

for example below i use Enumerable.Range(10 ,15).   I want to be able to iterate like this within the range. 10.00, 10.01, 10.02, 10.03, 10.04, 10.05. 10.06, 10.07, 10.08, 10.09, 10.10 all the way to 15.00 instead 10, 11, 12, 13, 14, 15

StreamWriter sw = new StreamWriter("darnell2.txt");

            sw.WriteLine("  X   |   Y");
            sw.WriteLine("-------------");

            foreach (int i in Enumerable.Range(10 ,15))
            {
                decimal x = i / 1000m;

                string xOutput = String.Format("{0:F2} | {1:F2}", x, x + .03m);

                sw.WriteLine(xOutput);
            }



            sw.Close();

Vuples you are one of the greatest to ever walk the face of the earth, I had a brain freeze, i think may work, I trying to get out of using for loops , I use forloops in ansi C and c++, i try to think straight c sharp when i am in the c sharp environment, to broaden my horizon. How would you do this in linq. I am going to test now using the Enumerable. Brb. give me 10minutes

To use foreach, you need a sequence i.e. something that implements IEnumerable.

You could do it using the LINQ method, Enumerable.Range, like this:

using System;
using System.IO;
using System.Linq;

class Program
{

   static void Main()
   {
      StreamWriter sw = new StreamWriter("darnell2.txt");
      sw.WriteLine("  X   |   Y");
      sw.WriteLine("-------------"); 

      foreach(int i in Enumerable.Range(1000, 501))
      {
         decimal x = i / 100m; 
         sw.WriteLine(String.Format("{0:F2} | {1:F2}", x, x + .03m));
      }                                          
     
      sw.Close();
   }
}    
 
You could also avoid using the temporary variable, x, by changing the foreach statement to:

      foreach(int i in Enumerable.Range(1000, 501))

      {

         sw.WriteLine(String.Format("{0:F2} | {1:F2}", i/100m, (i + 3)/ 100m));

      }     

thats was truly and error when i say y output limit. sorry.

thanks you guys, I actually design the logic using  the for loop like you guys did above, I was trying to come up with new way to simple give two limits and  evaluate the Y value between the limits, like you guys did above. Is there another way in c sharp to do this without using the for loop to produce this logic. Is there a way to produce this logic with a foreach or something?

As it takes 5 minutes to code, I don't know why you're worrying about coming up with a good design.

Here it is as a console app though, as there are 501 pairs of numbers, I've written them to a file rather than to the console:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;

namespace interest_calculation
{
  class Program
  {
  static void Main(string[] args)
  {
  double X = 0.00F;
  double Y = 0.00F;
  String Dummy_x = null;   //EDITED
  String Dummy_y = null;
  Console.Write("Please Enter X value : ");
  X = Convert.ToDouble(Console.ReadLine());
  Console.WriteLine();
  while (true)
  {
  Y = X + 0.03;
  if(Y < 15)
  {
  Dummy_x = String.Format("{0:0.00}", X);    //EDITED
  Dummy_y = String.Format("{0:0.00}", Y);
  Console.WriteLine("X is : " + Dummy_x + " || " + "Y is : " + Dummy_y);   //EDITED
  X = Y;
  }
  }
  }
  }
  }


This is the exact code which you asked for i guess. For further assistance post a reply.

You said your Y value limit is 15.00 but you are still showing up 15.03 in the example you stated. You want it in the Windows form or what?