Develop Reference

Program writes out chars as ascii codes, but only sometimes

I was bored so I decided to create a little rock paper scissors game. It isn't complete because I only wanted to include necessary code. It looks like this:
class Program
{
static void Main(string[] args)
{
char[] enemyznak = new char[9];
char[] znak = enemyznak;
char input;
Console.WriteLine("A as in pAper, D as in Diorite, S as in Scissors");
Random random = new Random();
while (true)
{
Input:
input = Console.ReadLine()[0];
switch (input)
{
case 'A': znak = Paper(znak);
break;
case 'D': znak = Rock(znak);
break;
case 'S': znak = Scissors(znak);
break;
default: Console.WriteLine("Unknown Character"); goto Input;
}
switch (random.Next(0,3))
{
case 0: enemyznak = Paper(enemyznak);
break;
case 1: enemyznak = Rock(enemyznak);
break;
case 2: enemyznak = Scissors(enemyznak);
break;
}
Console.WriteLine(znak[0] + znak[1] + znak[2] + " " + enemyznak[0] + enemyznak[1] + enemyznak[2]);
Console.WriteLine(znak[3] + znak[4] + znak[5] + " " + enemyznak[3] + enemyznak[4] + enemyznak[5]);
Console.WriteLine(znak[6] + znak[7] + znak[8] + " " + enemyznak[6] + enemyznak[7] + enemyznak[8]);
}
}
static char[] Rock(char[] znak)
{
// just like Scissors except different characters
}
static char[] Scissors(char[] znak)
{
znak[0] = 'o';
znak[1] = ' ';
znak[2] = '/';
znak[3] = ' ';
znak[4] = '¤';
znak[5] = ' ';
znak[6] = 'o';
znak[7] = ' ';
znak[8] = '\\';
return znak;
}
static char[] Paper(char[] znak)
{
// just like Scissors except different characters
}
}
During the printing out phase, it shows the player's symbol as weird numbers (such as 190 228 235 for Scissors). However, enemy symbol is written out as it should be, in characters. I tried comparing the segments but they seem the same to me, so what causes this inconsistency?

You bumped into C# operator priority and its implicit behavoiur.
To fully understand the behaviour, let us start from three things:
what your code is actually calling
how the + operator works
what is char type
1. What your code is actually calling
Let us focus on the given line:
Console.WriteLine(znak[0] + znak[1] + znak[2] + " " + enemyznak[0] + enemyznak[1] + enemyznak[2]);
Once you step in while debigging, you will see that the signature of this method is: public static void WriteLine(string? value)
2. How the + operator works
See documentation: + and += operators (C# reference)
In short:
When one or both operands are of type string, the + operator concatenates the string
3. What is char type
See documentation: char (C# reference)
In short:
Moreover, for char operands, arithmetic and bitwise logical operators perform an operation on the corresponding character codes and produce the result of the int type.
We can gather all those details to find out what is going on:
We are calling Console.WriteLine(znak[0] + znak[1] + znak[2] + " " + enemyznak[0] + enemyznak[1] + enemyznak[2]); (so WriteLine(string? value))
2, Program to be able to call WriteLine(string? value) will create a variable of type string? with the following value: znak[0] + znak[1] + znak[2] + " " + enemyznak[0] + enemyznak[1] + enemyznak[2]
As we now from 2, adding char and char with + operator will result in int:
znak[0] 111 'o' char
znak[1] 32 ' ' char
znak[2] 47 '/' char
...
so znak[0] + znak[1] = 143, 143 + znak[2] = 190 (such as 190 228 235 for Scissors)
Now as we now from 3 When one or both operands are of type string, the + operator concatenates the string so: 190 + " " = "190" + " " = "190 ".
Now on the left hand side we have a string. So (as we know from 3) "190 " + + enemyznak[0] + enemyznak[1] + enemyznak[2] will result in string.
You can run the following experiment:
add empty string at the very beginning:
Console.WriteLine("" + znak[0] + znak[1] + znak[2] + " " + enemyznak[0] + enemyznak[1] + enemyznak[2]);
Console.WriteLine("" + znak[3] + znak[4] + znak[5] + " " + enemyznak[3] + enemyznak[4] + enemyznak[5]);
Console.WriteLine("" + znak[6] + znak[7] + znak[8] + " " + enemyznak[6] + enemyznak[7] + enemyznak[8]);
See what will happen. As you have string + char, it will result in string.

How to sort an array based on specific index [duplicate]

This question already has answers here:
How to sort an array containing class objects by a property value of a class instance? [duplicate]
(2 answers)
Closed 7 years ago.
I Have an array like below code :
struct Book_Struct
{
public string Title;
public string Auther;
public int Date;
public int ID;
}
static void Print(Book_Struct[] a, int b)
{
for (int i = 0; i < b; i++)
{
Console.WriteLine(" Name of Book " + (i + 1) + " is : " + "\" " + a[i].Title + " \"");
Console.WriteLine("Auther of Book " + (i + 1) + " is : " + "\" " + a[i].Auther + " \"");
Console.WriteLine(" Date of Book " + (i + 1) + " is : " + "\" " + a[i].Date + " \"");
Console.WriteLine(" ID of Book " + (i + 1) + " is : " + "\" " + a[i].ID + " \"");
Console.WriteLine("\n---------------------------------\n");
}
}
I want sort this array based on for example Title of Books. How do i it?

You could use Array.Sort:
Array.Sort(a, (b1, b2) => b1.Title.CompareTo(b2.Title));
or LINQ:
a = a.OrderBy(book => book.Title).ToArray();
The latter needs to recreate the array.
As an aside, use a class instead of a mutable struct.

Use LINQ's OrderBy to sort the array:
a = a.OrderBy(x => x.Title).ToArray();
Reference

Extracting common terms with MathNet Symbolics

I'm using MathNet Symbolics to handle the symbolic algebra portion of a program I'm working on. The general use is create a pair of symbolic formulas, and then divide those two formulas. This works quite well most of the time. However, sometimes, it does not want to do more complex simplification. For example:
(512*r*t*w + 2048*r*t^2*w)
-----------------------------------------------------------------------
(512*r*t*w + 512*r^2*t*w + 3072*r*t^2*w + 3072*r^2*t^2*w + 1024*r*t^3*w)
With some work, I've been able to have it eliminate w from the equation, as it is in all terms top and bottom:
(512*r*t + 2048*r*t^2)
--------------------------------------------------------------
(512*r*t + 512*r^2*t + 3072*r*t^2 + 3072*r^2*t^2 + 1024*r*t^3)
However, I cannot figure out how to make it find common terms:
(512*r*t)*(1 + 4*t)
--------------------------------------
(512*r*t)(1 + r + 6*t + 6*r*t + 2*t^2)
And eliminate these terms:
(1 + 4*t)
-----------------------------
(1 + r + 6*t + 6*r*t + 2*t^2)
I've been using Wolfram Alpha as my gold standard for checking my work. The code from LinqPad I've been working on most of the afternoon, that gets my the elimination of w:
var h1 = MathNet.Symbolics.Infix.ParseOrUndefined("(1/8)*r*t*w + (1/2)*r*t^2*w");
var h2 = MathNet.Symbolics.Infix.ParseOrUndefined("(1/8)*r*t*w + (1/8)*r^2*t*w + (3/4)*r*t^2*w + (3/4)*r^2*t^2*w + (1/4)*r*t^3*w");
Infix.Print(Rational.Expand(h1/h2)).Dump(); //Prints (512*r*t*w + 2048*r*t^2*w)/(512*r*t*w + 512*r^2*t*w + 3072*r*t^2*w + 3072*r^2*t^2*w + 1024*r*t^3*w)
var tot = Rational.Expand(h1 / h2);
var simplified = true;
do
{
simplified=false;
foreach (var v in Rational.Variables(tot))
{
var result = Polynomial.Divide(v, h1, h2);
if (!result.Item1.Equals(MathNet.Symbolics.Expression.Zero))
{
simplified = true;
tot = result.Item1;
break;
}
}
}while(simplified);
tot = Rational.Expand(tot);
Infix.Print(tot).Dump(); //Prints (512*r*t + 2048*r*t^2)/(512*r*t + 512*r^2*t + 3072*r*t^2 + 3072*r^2*t^2 + 1024*r*t^3)
Can someone give me pointers to how to proceed with MathNet? I've tried various combinations of functions from Rational and Polynomial, and have not been able to move past this point.

I've just published a new Math.NET Symbolics release v0.6.0 which includes a new Rational.Reduce routine that removes such common simple factors (also executed as part of Rational.Expand):
var h1 = Infix.ParseOrThrow("(1/8)*r*t*w + (1/2)*r*t^2*w");
var h2 = Infix.ParseOrThrow("(1/8)*r*t*w + (1/8)*r^2*t*w + (3/4)*r*t^2*w + (3/4)*r^2*t^2*w + (1/4)*r*t^3*w");
var q1 = h1/h2;
Infix.Print(q1);
// returns: ((1/8)*r*t*w + (1/2)*r*t^2*w)/((1/8)*r*t*w + (1/8)*r^2*t*w + (3/4)*r*t^2*w + (3/4)*r^2*t^2*w + (1/4)*r*t^3*w)
var q2 = Rational.Expand(q1);
Infix.Print(q2);
// returns: (1 + 4*t)/(1 + r + 6*t + 6*r*t + 2*t^2)
Unfortunately quite a few of the univariate polynomial and rational routines like the new square-free factorization do not have a multivariate counterpart yet. Univariate routines expect one symbol parameter, while multivariate ones expect a symbol set.

Count the number of rows in each column

How can I count number of rows in specified column in a Excel sheet?
For example I have 2 columns in a spreadsheet:
A B
--- -----
abc hi
fff hello
ccc hi
hello
The result should look like:
count of A column is 3
count of B column is 4
How can I do this using Microsoft Interop?

The approach suggested by Doug Glancy is accurate and simple to be implemented. You can write the function and retrieve the value from a cell not seenable by the user (ZZ1000, for example). The code is straightforward:
Range notUsed = curSheet.get_Range("ZZ1000", "ZZ1000");
string targetCol = "A";
notUsed.Value2 = "=COUNTA(" + targetCol + ":" + targetCol + ")";
int totRows = Convert.ToInt32(notUsed.Value2);
notUsed.Value2 = "";
UPDATE ---
From your example I understood that you were looking for the total number of non-empty cells, what COUNTA delivers. But, apparently, this is not the case: you want the row number of the last non-empty cell; that is, by using a more descriptive example:
C
---
abc
fff
ccc
hello
You don't want to count the number of non-empty cells (4 in this case; what COUNTA delivers), but the position of "hello", that is, 5.
I don't like relying on Excel formulae too much, unless for clearly-defined problems (like yours, as I understood it initially). Excel formulae deliver still the best solution for what you really want (although its complexity is right "in the limit"). To account for the situation as described above, you can rely on MATCH. If your cells contain text (at least one letter per cell), the code can be changed into:
notUsed.Value2 = "=MATCH(REPT(\"z\",255)," + targetCol + ":" + targetCol + ")";
In case of having numeric values (not a single letter in the cell):
notUsed.Value2 = "=MATCH(LOOKUP(" + Int32.MaxValue.ToString() + "," + targetCol + ":" + targetCol + ")," + targetCol + ":" + targetCol + ")";
If you want to account for both options, you would have to combine these equations: you can create a new formula including both; or you might rely on C# code (e.g., get the values from both equations and consider only the bigger one).
Bear also in mind that you have to account for cases where no matches are found. Here you have a code accounting for both situations (letters and numbers via C# code) and for no matches:
notUsed.Value2 = "=MATCH(REPT(\"z\",255)," + targetCol + ":" + targetCol + ")";
int lastLetter = Convert.ToInt32(notUsed.Value2);
if (lastLetter == -2146826246)
{
lastLetter = 0;
}
totRows = lastLetter;
notUsed.Value2 = "=MATCH(LOOKUP(" + Int32.MaxValue.ToString() + "," + targetCol + ":" + targetCol + ")," + targetCol + ":" + targetCol + ")";
int lastNumber = Convert.ToInt32(notUsed.Value2);
if (lastNumber == -2146826246)
{
lastNumber = 0;
}
if (lastNumber > totRows)
{
totRows = lastNumber;
}

This should do it:
private static int GetRowsInColumnOnWorkSheetInWorkbook(string workbookName, int worksheetNumber, int workSheetColumn)
{
return new Excel.Application().Workbooks.Open(workbookName)
.Sheets[worksheetNumber]
.UsedRange
.Columns[workSheetColumn]
.Rows
.Count;
}
You could have the following override also:
private static int GetRowsInColumnOnWorkSheetInWorkbook(string workbookName, string worksheetName, int workSheetColumn)
{
return new Excel.Application().Workbooks.Open(workbookName)
.Sheets[worksheetName]
.UsedRange
.Columns[workSheetColumn]
.Rows
.Count;
}
It's slightly longer than the other answer, but I think this is more readable, and simpler.

Data lost while adding string to listbox

I am cycling through the contents of a two-dimensional array containing the result of a Punnett Square calculation for gene crosses. I need to summarize the result so that the user can readily see the unique instances. I can accomplish this by putting the result into a text box, but when I try and use a ListBox to display the data, part of the information is getting lost, namely a translation of the AaBBCc type data to something that directly relates to the traits that the user initially selected.
This is the main block of code for the operation:
foreach (string strCombination in arrUniqueCombinations)
{
int intUniqueCount = 0;
decimal decPercentage;
foreach (string strCrossResult in arrPunnettSQ)
{
if (strCrossResult == strCombination)
{
intUniqueCount++;
}
}
decPercentage = Convert.ToDecimal((intUniqueCount*100)) / Convert.ToDecimal(intPossibleCombinations);
txtReport.AppendText(strCombination + " appears " + intUniqueCount.ToString() + " times or " + decPercentage.ToString() + "%."+ Environment.NewLine);
lstCrossResult.Items.Add(DecodeGenome(strCombination) + " appears " + intUniqueCount.ToString() + " times or " + decPercentage.ToString() + "%.");
}
For appending the data to the textbox I use this code and it works perfectly:
txtReport.AppendText(DecodeGenome(strCombination) + " appears " + intUniqueCount.ToString() + " times or " + decPercentage.ToString() + "%."+ Environment.NewLine);
Giving the result:
Trait 1 Het.,Trait 3 appears 16 times or 25%.
For adding the result to a list box, this works:
lstCrossResult.Items.Add(strCombination + " appears " + intUniqueCount.ToString() + " times or " + decPercentage.ToString() + "%.");
Giving the result:
AaBBCc appears 16 times or 25%.
But the contents of strCombination is AaBBCc and I need it translated to "Trait 1 Het.,Trait 3", which I accomplish with this bit of code:
private string DecodeGenome(string strGenome)
{
string strTranslation = "";
int intLength = strGenome.Length;
int intCounter = intLength / 2;
string[] arrPairs = new string[intLength / 2];
//Break out trait pairs and load into array
for (int i = 1; i <= intLength; i++)
{
arrPairs[i / 2] = strGenome.Substring((i-1),2);
i++;
}
foreach (string strPair in arrPairs)
{
char chFirstLetter = strPair[0];
char chSecondLetter = strPair[1];
intCounter = intCounter - 1;
if (Char.IsUpper(chFirstLetter))
{
if (!Char.IsUpper(chSecondLetter))
{
if (intCounter > 0)
{
txtReport.AppendText(GetDescription(strPair.Substring(0, 1)) + " Het.,");
}
else
{
txtReport.AppendText(GetDescription(strPair.Substring(0, 1)));
}
}
}
else
{
if (!Char.IsUpper(chSecondLetter))
{
if (intCounter > 0)
{
txtReport.AppendText(GetDescription(strPair.Substring(0, 1)) + ",");
}
else
{
txtReport.AppendText(GetDescription(strPair.Substring(0, 1)));
}
}
}
}
return strTranslation;
}
That has no problem displaying in a text box, but when I try and put it as an item into a list box it turns it into null. Instead of:
"Trait 1 Het.,Trait 3 appears 16 times or 25%."
I get:
" appears 16 times or 25%."
I have tried adding the results to an ArrayList, then populating the listbox after everything is processed, but the result is the same.
Any clues as to why the list box is not accepting the translated AaBBCc information would be greatly appreciated.

strTranslation is never set. Everything is pushed to txtReport.AppendText