C# Discussion Boards - CodeProject

Recursive function to display the number of nodes of a singly connected list?

9-Nov-05 0:35

Could someone give me an algorithm of a recursive function to return the max key of nodes of a singly connected list?

ektoras9-Nov-05 0:31

Re: Recursive function to display the number of nodes of a singly connected list?

9-Nov-05 0:31

Could someone give me an algorithm of a recursive function to display-NOT TO RETURN-the number of nodes of a singly connected list?

J4amieC9-Nov-05 2:16

Re: Recursive function to display the number of nodes of a singly connected list?

9-Nov-05 2:16

I am probably misunderstanding your question, but any implementation of a List (ArrayList, LinkedList etc) should expose a Count property, and so your question of how to display this is down to where you want to display it.

on the console:

Console.WriteLine(myList.Count);

in a messageBox

MessageBox.Show(miList.Count.ToString());

sorry if ive misunderstood Wink | ;)

ektoras9-Nov-05 3:36

Re: Recursive function to display the number of nodes of a singly connected list?

9-Nov-05 3:36

This is not a C# question but an algorithm question for my homework at university.

Wjousts9-Nov-05 4:18

Wjousts

9-Nov-05 4:18

Perhaps you should do you own homework? You learn a lot more that way. This isn't a difficult question.

Re: Recursive function to display the number of nodes of a singly connected list?

ektoras9-Nov-05 7:20

Re: Recursive function to display the number of nodes of a singly connected list?

9-Nov-05 7:20

It is absolutely sure that I can not do that, although I have tried very much. Any idea?

Wjousts9-Nov-05 7:35

Wjousts

9-Nov-05 7:35

What have you tried? Show people that you are thinking about this and not just too lazy to do your homework and you'll find people are much more responsive.

You need to write a recursive function, something like this (you fill in the blanks):

<code>
public int CountNodes(Node n)
{
    if(ExitCondition)    // what's your exit condition?
    {
        return ?;        // what should you return for your base 
case?
    }
    else
    {
    // what do you need to return here. What are you going to pass to the recursive call?
        return ? + CountNodes(?);     
    } 
}
</code>

Re: Recursive function to display the number of nodes of a singly connected list?

J4amieC9-Nov-05 4:45

Re: Recursive function to display the number of nodes of a singly connected list?

9-Nov-05 4:45

while I Agree with wjousts assertion that a) this is not a particularly difficult question and b) you should do your own homework Wink | ;)

- I will provide some assistance.

You must know what a linked list is, if not go back and refer to your course notes. Recursion you probably also know about - essentially calling a function from itself (or put another way "to understand recursion, you must first understand recursion /geekhumour)

So, to help write this algorithm, I find it easy to start off in pseudo-code

while {not at end of list)
    Incrememnt counter
loop
return counter

Now, I know you super-highlight-stressed that you want it DISPLAYED and not RETURNED!!11 (your homework said display it right?) however in order to dispaly something...it must first be returned from somewhere.

Turning the above into a "recursive function" is the bit you've got to do. If this is not enough to get you going on your homework, then seriously consider whether you should be studying a subject you cannot do!

Good luck.

ektoras9-Nov-05 7:38

Re: Recursive function to display the number of nodes of a singly connected list?

9-Nov-05 7:38

My English is not good.
But I mean something like that:

int count(POINTER head)<br />
{<br />
	return head!=NULL ? count(head->next)+1 : 0 ;<br />
}

But not to return the value. I WANT TO DISPLAY THE VALUE.(and this is difficult)

J4amieC9-Nov-05 9:27

Re: Recursive function to display the number of nodes of a singly connected list?

9-Nov-05 9:27

Where do you want to display it? In a window? on a command line?

ektoras9-Nov-05 9:34

Re: Recursive function to display the number of nodes of a singly connected list?

9-Nov-05 9:34

on a Command Line.

J4amieC9-Nov-05 10:00

Re: Recursive function to display the number of nodes of a singly connected list?

9-Nov-05 10:00

Console.WriteLine(myList.Count(myList.FirstNode))

seriously, you couldnt work this out? Swap to a different course while you still can.

ektoras9-Nov-05 10:27

URGENT!!!PLEASE...DataGrid Drag_Drop!!

9-Nov-05 10:27

It is a Data Structure work J4amieC. Anyway thank you.

GDI+ metafile

Timothy Tim9-Nov-05 0:23

Timothy Tim

9-Nov-05 0:23

Hi folks,

I have project writing rich text document on metafile using GDI
Now I'm trying to make it using GDI+
Problem: I can't draw it precisely!!

Test sample: create metafile 10x10 inces, draw strips 10, 9, 8 inches long:

<br />
RectangleF frame = new RectangleF(0f, 0f, 10f, 10f);<br />
Metafile mf;<br />
Graphics g1;<br />
<br />
using(Graphics gr = CreateGraphics())<br />
{<br />
  IntPtr dc = gr.GetHdc();<br />
  mf = new Metafile(@"c:\inch.emf", dc, frame, MetafileFrameUnit.Inch, EmfType.EmfOnly);<br />
  gr.ReleaseHdc(dc);<br />
}<br />
g1 = Graphics.FromImage(mf);<br />
g1.PageUnit = GraphicsUnit.Inch;<br />
g1.DrawLine(Pens.Green, 0F, 1F, 10F, 1F);<br />
<br />
g1.DrawLine(Pens.Green, 0F, 3F, 9F, 3F);<br />
g1.DrawLine(Pens.Green, 0F, 5F, 8F, 5F);<br />
g1.DrawLine(Pens.GreenYellow, 1f, 0f, 1f, 10f);<br />
g1.DrawLine(Pens.GreenYellow, 3f, 0f, 3f, 9f);<br />
g1.DrawLine(Pens.GreenYellow, 5f, 0f, 5f, 8f);      <br />
<br />
g1.Dispose();<br />
mf.Dispose();<br />

Strips are shorter than needed!!
Using other units (Milimeter, Pixel, Point, Document) produces different results - all invalid

Question: how to create precise EMF - with definite size

WBR Tim

innocent738-Nov-05 23:56

innocent73

8-Nov-05 23:56

Hi folks,
I have a data grid.And I want to drag a cell's context into datagrid's caption text by dragging it. How can I do this...
Please help

-- modified at 9:29 Wednesday 9th November, 2005

Algorithm Question - Urgent Help Needed

allenmpcx8-Nov-05 23:40

allenmpcx

8-Nov-05 23:40

Hello, I am presented with the following problem and have tried desperately (over 12 hours) to solve it:

I have a string say "011010101" and I want to parse this string based on a table of values:

i = 0
m = 011
k = 10
e = 101

I want to construct an algorithm that will go through the string above and parse it assigning each value to their corresponding table value. Looking at it, I know that the string would become "011" , "0" , "10" , "101" which for this example would be "mike" in that order. Since "i" is the first thing I check, my code tries to form "0", "11010101", and nothing else will get extracted. I don't need code, but maybe some concepts I could build off of? Any help would be greatly appreciated.

I love to program!

J4amieC9-Nov-05 0:19

9-Nov-05 0:19

A few thoughts:

if i=0 and m=011 how do you determine, when parsing, that a value of 0 is 'i' or the start of 'm'? The answer is that you need to have a defined way of making each value unique. A pointer for you would be to base your 0's and 1's from morse code, where this uniqueness is enforced - also morse (in case you dont know) is made up of dots and dashes - very fitting with your 1's and 0's

Ok, onto parsing the string - take a look at StringTokenizer's - there are at least two articles here on CP about the principle - and it is basically what you want - in (unwritten) code;

StringTokenizer st = new StringTokenizer("011010101");<br />
string convertedString = "";<br />
while(st.HasMoreTokens)<br />
{<br />
    char nextChar = st.NextToken();<br />
    convertedString += nextChar;<br />
}

HymanRoth9-Nov-05 0:43

HymanRoth

9-Nov-05 0:43

This problem is potentially non-trivial.

There are two things your forgot to specify. The first is whether there can be more than one correct parsing for each string. For example, your string parsed to "mike", but (with the right additional codes) it could also have parsed to pratically any other alphanumeric output. This is key in determining when and how the algorithm should terminate. The second problem is one of scope. How long is the input string and how big is the table of values? The way the algorithm will work is to search through the space of ALL POSSIBLE parsings and output those that complete. Clearly, the bigger your input string and lookup table get, the more the chances of seeing a 'combinatorial explosion'.

If you answer these questions, I will help you write the algorithm. Please let me know if you are comfortable with embedded recursion, or your pefer iterative processes. The former is much more elegant, but with big inputs could create memory problems.

-- modified at 6:45 Wednesday 9th November, 2005

allenmpcx9-Nov-05 0:47

allenmpcx

9-Nov-05 0:47

I prefer embedded recursion. There can be more than one correct parsing for each string, and for this example, the table is limited to the alphabet (lower-case and upper-case) and also '\n', ' ', and '\t'.

I love to program!