Re: Convert String to decimal - C# Discussion Boards

Guffa22-Feb-06 9:16

Guffa

22-Feb-06 9:16

That depends on the scope of the references you use. If you don't have references the previous arrays, the memory will be garbage collected when needed.

You should remove the reference (e.g. setting it to null) as soon as you don't need any of the arrays.

If the references may still point to old arrays when you enter the method, you'd better release those before you allocate the new arrays:

start_volumn = null;<br />
pre_volumn = null;<br />
post_volumn = null;<br />
best_end_volumn = null;<br />
start_volumn = new double[TP];<br />
pre_volumn = new double[TP];<br />
post_volumn = new double[TP];<br />
best_end_volumn = new double[TP];

This way the memory will be available for garbage collection if needed. If you don't do this, the reference will not be released until the new array is allocated and the new reference replaces the old.

If possible, you should consider reusing the same arrays instead of allocating new ones over and over.

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b { font-weight: normal; }

Colin Angus Mackay22-Feb-06 11:28

Colin Angus Mackay

22-Feb-06 11:28

Guffa wrote:
If you don't do this, the reference will not be released until the new array is allocated and the new reference replaces the old.

But it is still up to the garbage collector to take back the memory. In an array like this it will instantly go into the third-generation heap when it was created, and so wouldn't be collected for a while anyway.

Maybe I'm spoilt. I work on server systems most of the time (6+Gb of RAM) so I never really worry about these things because I know that once it goes out of scope, with no other references, the garbage collector will get it when it needs to.

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Guffa22-Feb-06 11:42

Guffa

22-Feb-06 11:42

Yes, but the memory can't be taken back as long as there is a reference to the array. Compare these two codes:

ref = new double[5000];<br />
ref = null;<br />
// now the first array can be garbage collected<br />
ref = new double[1000];

Without releasing the reference:

ref = new double[5000];<br />
ref = new double[1000];<br />
// the first array can't be garbage collected until here

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Convert String to decimal

Colin Angus Mackay22-Feb-06 11:50

Colin Angus Mackay

22-Feb-06 11:50

Hence my second paragraph about being spoilt working on server systems with gargantuan amounts of memory.

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cppdotnet22-Feb-06 3:51

cppdotnet

22-Feb-06 3:51

Hi
I have a decimal value which i want to convert to string but it drops off .0 (decimal)

I can't format since whatever value in decimal I want it as it is in string

ex. 88.99 88.00 88.0 or just 88

Thanks

Thanks

Judah Gabriel Himango22-Feb-06 4:10

22-Feb-06 4:10

double val = 88.00;
string valStringWithZeroes = string.Format("{0:0.00}", val);

You can see a list of string formatting options from this blog posting[^].

cppdotnet22-Feb-06 4:16

cppdotnet

22-Feb-06 4:16

This is great but doesn't work if i have 88.0 it will format that to 88.00

I want which shows # as it is ... like 88.0 or 88888.888

Thanks

Judah Gabriel Himango22-Feb-06 4:29

22-Feb-06 4:29

Your problem is that

double val = 88.0;

Is the same value as

double val = 88.0000;

They're the same in the real mathematical sense of decimal values, as well as the same in the CLR. So, there's no way for you to print out whether it's 88.0 or 88.0000 if you're storing it as a double. I'm not sure whether there's a type in the CLR that stores an arbitrary number of decimal places as part of the value type itself.

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Dan Neely22-Feb-06 4:37

Dan Neely

22-Feb-06 4:37

Judah Himango wrote:
They're the same in the real mathematical sense of decimal values, as well as the same in the CLR. So, there's no way for you to print out whether it's 88.0 or 88.0000 if you're storing it as a double. I'm not sure whether there's a type in the CLR that stores an arbitrary number of decimal places as part of the value type itself.

For something not being modifed in code, String.

If you need to use it arithmatically, I'd suggest looking at scientific libraries for a class that handles significant figures, because with SF 88.1 != 88.10. The former represents the range 88.05

Judah Gabriel Himango22-Feb-06 4:44

22-Feb-06 4:44

dan neely wrote:
SF 88.1 != 88.10

I knew someone would call me out on this. It all depends on the context really; if we're talking about precision, yes, they are obviously not the same. If we're talking about simple arithmetic, they are the same value if precision is ignored (which is often the case in arithmetic). Anyways...for his uses, he'll need to either get a scientific library or write a type that preserves decimal precision, so it seems. I can't find any type in the CLR that preserves decimal precision.

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cppdotnet22-Feb-06 5:02

cppdotnet

22-Feb-06 5:02

I know 88 is same as 88.0 or 88.00 but according to my requriments i have two #'s coming in ex 00.00 as string aand 88.00 as decimal .... now i have to compare string # to decimal which means that my number should have 2 digit before decimal and 2 digit after

another example one # is 0.0 measn another # should have one digit before decimal and one digit after decimal ... regardless of 8.0 is same as 8.00 or 8 ... in my case only 8.0 or 8.1 0r 8.2 or 9.1 are the valid digit since one digit after decimal and one digit before decimal

That's why i can't use formating since i don't what's the 1st # will look like which is string and what's the 2nd # looks like which is decimal

Thanks

Dan Neely22-Feb-06 6:15

Dan Neely

22-Feb-06 6:15

Judah Himango wrote:
dan neely wrote:
SF 88.1 != 88.10

I knew someone would call me out on this. It all depends on the context really; if we're talking about precision, yes, they are obviously not the same.

true. I mainly included it since I wasn't sure what the OP wanted, and wanted to epxlain why the class was doing what it was and check for potential side effects instead of assuming it was a 'double but keeps empty decimal places' and then getting burned over it enforcing SF, or the like.

Having Scrollbars to MDI form?

Qhalis22-Feb-06 4:59

Qhalis

22-Feb-06 4:59

The problem is that there is no single format that will achieve your goal

Say you have 88.0 and 88888.888

Console.WriteLine("{0 Blush | :O

##}", num)

will give you

88.0
88888.888

the problem is that if you have another number of finer precision, say 99.1234, it will be rounded to 99.124.

If you use the general format g

Console.WriteLine("{0:g}", num)

then you will get

88
88888.888
99.1234

If you have a hard need to display 88 as 88.0 then you will probably need to use two format strings

Dim nums() As Double = {88, 88888.888}
Dim numFmt As String

For Each num As Double In nums

Dim tmpNum As Double = System.Math.Abs(num)
If (System.Math.Floor(tmpNum) = tmpNum) Then
numFmt = "#.0"
Else
numFmt = "g"
End If

Dim exprFmt As String = "{0:" & numFmt & "}"

Console.WriteLine(exprFmt)
Console.WriteLine(String.Format(exprFmt, num))

Next

End Sub

NOTE: When testing this, it works well for Doubles but not singles. Don't know why

hth,
Alan.

if (

majidbhutta22-Feb-06 3:50

majidbhutta

22-Feb-06 3:50

Well! Dears.
i have an mdi form in which i open differnet child forms . when both parent and child are maximized its ok but when i restore the MDI parent form it disturbs the layout of Child form that was Maximized in MDI. What i want is that when i restore MDI form it doesnt disturb the layout design of Child form instead it (MDI form) gets Horizantal and vertical scroll bar keeping the Child Form Maximized and undisturbed. How to do that.
Thnx in Advance.

Re: Having Scrollbars to MDI form?

Judah Gabriel Himango22-Feb-06 7:13

22-Feb-06 7:13

If you're asking how to automatically get scrollbars to some control, look at System.Windows.Forms.ScrollableControl. When some control added to a ScrollableControl extends beyond the visible portion of the ScrollableControl, scrollbars will automatically appear.

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Save with date format

mostafa_h22-Feb-06 3:29

22-Feb-06 3:29

hi !
I want to save the value of date with the using DateTimePicker Control in a sql table with the date Format .

...<br />
try{<br />
strSQL ="update mytable set name='"+txtName.Text+  "',mydate='"+DateTimePicker1.???? ......

Any guid is very appereciated.
Regards

s_mostafa_h

-- modified at 9:30 Wednesday 22nd February, 2006

Judah Gabriel Himango22-Feb-06 4:03

22-Feb-06 4:03

string commandText = "UPDATE mytable SET name = @name, mydate = @date";
SqlCommand command = new SqlCommand(commandText, myConnection);
command.Parameters.Add(new SqlParameter("@name", txtName.Text));
command.Parameters.Add(new SqlParameter("@date", dateTimePicker1.Value));

Tech, life, family, faith: Give me a visit.
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mostafa_h22-Feb-06 4:45

22-Feb-06 4:45

I Wrote this :

try{<br />
strSQL ="update mytable set name='"+txtName.Text+ "',mydate='"+DateTimePicker1.Value+"'";<br />
cnSQL = new SqlConnection(Connectionstring);<br />
cnSQL.Open();<br />
cmSQL = new SqlCommand(strSQL, cnSQL);<br />
cmSQL.ExecuteNonQuery();<br />
cnSQL.Close();<br />
cmSQL.Dispose();<br />
cnSQL.Dispose();<br />
} <br />
catch(SqlException e)<br />
{<br />
MessageBox.Show(e.Message, "Error");<br />
}

But I have this Error :
syntax error converting datetime from character string
the type of mydate field is datetime .
please guide me !
thanks

s_mostafa_h

Judah Gabriel Himango22-Feb-06 4:48

22-Feb-06 4:48

mostafa_h wrote:
strSQL ="update mytable set name='"+txtName.Text+ "',mydate='"+DateTimePicker1.Value+"'";

Don't do that. You're opening yourself up to SQL injection attacks[^]. I showed you the proper way to do it in my last reply (by using SqlParameter objects). If you follow that course of action, you won't get the error.

Tech, life, family, faith: Give me a visit.
I'm currently blogging about: Connor's Christmas Spectacular!
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mostafa_h22-Feb-06 6:24

22-Feb-06 6:24

thanks of your guide !
REGARDS ,

s_mostafa_h

Le centriste22-Feb-06 6:28

Le centriste

22-Feb-06 6:28

mostafa_h wrote:
Any guid is very appereciated

{DB618332-94FC-4171-BFCC-BA654F5EED58}

--------

"I say no to drugs, but they don't listen."
- Marilyn Manson

mostafa_h22-Feb-06 7:25

22-Feb-06 7:25

Michel Prévost wrote:
{DB618332-94FC-4171-BFCC-BA654F5EED58}

{DB618332-94FC-4171-BFCC-BA654F5EED58}
Any guide is very appreciated . Confused | :confused:

excuse me for my poor english .

s_mostafa_h

Le centriste22-Feb-06 7:26

Le centriste

22-Feb-06 7:26

No problem, english is not my first language either. I just hope you are not angry at me, I couldn't resist doing the joke. Blush | :O

I guess you know what a GUID is...

--------

"I say no to drugs, but they don't listen."
- Marilyn Manson

-- modified at 13:26 Wednesday 22nd February, 2006

mostafa_h22-Feb-06 11:12