| Groups | Blog | Home |
c# : using delegate
The following piece of code (between comment /***************/ line )works
fine. You can test is in console/win form/web page. Just print strResult. /**************************************************/ public delegate double DlgFn(double x); public static double f1(double x) { return Math.Exp(-(x * x)); //function to be integrated by Simpson's rule } public class Integral { public static double Integrate(DlgFn f, double a, double b, int n) { double h = (b - a) / n;//step_size double sum = 0; sum += f(a) + f(b); for (int i = 1; i <= (n - 1); i += 2) sum += 4 * f(a + i * h); for (int i = 2; i <= (n - 1); i += 2) sum += 2 * f(a + i * h); return Math.Round((h / 3) * sum, 5); } } string strResult = Integral.Integrate(new DlgFn(f1), 0, 1, 100).ToString(); /**************************************************/ However it does not enable me to extend my application further. I want to replace the last line of code, string strResult = Integral.Integrate(new DlgFn(f1), 0, 1, 100).ToString(); with the following lines: double lLim= 0; double uLim= 1; double n =100; // step no. DlgFn myFn = new DlgFn(Integral.Integrate); string strResult =myFn(f1, lLim, uLim, new).ToString(); The reason for doing so is because the variables, lLim, uLim and n will be used in other methods in application code. I eagerly look forward for any useful hints/help that could get me move ahead. Thanks,
[quoted text, click to view]
On 9 May, 03:20, "ASP.NET explorer" <aspdotnet@learner> wrote: > The following piece of code (between comment /***************/ line )works > fine. You can test is in console/win form/web page. Just print strResult. > > /**************************************************/ > public delegate double DlgFn(double x); > > public static double f1(double x) { > return Math.Exp(-(x * x)); //function to be integrated by Simpson's > rule > } > public class Integral { > public static double Integrate(DlgFn f, double a, double b, int n) { > double h = (b - a) / n;//step_size > double sum = 0; > sum += f(a) + f(b); > for (int i = 1; i <= (n - 1); i += 2) sum += 4 * f(a + i * h); > for (int i = 2; i <= (n - 1); i += 2) sum += 2 * f(a + i * h); > return Math.Round((h / 3) * sum, 5); > } > } > string strResult = Integral.Integrate(new DlgFn(f1), 0, 1, > 100).ToString(); > /**************************************************/ > > However it does not enable me to extend my application further. > > I want to replace the last line of code, > string strResult = Integral.Integrate(new DlgFn(f1), 0, 1, 100).ToString(); > with the following lines: > > double lLim= 0; double uLim= 1; > double n =100; // step no. > DlgFn myFn = new DlgFn(Integral.Integrate); > string strResult =myFn(f1, lLim, uLim, new).ToString(); > > The reason for doing so is because the variables, lLim, uLim and n will be > used in other methods in application code. > > I eagerly look forward for any useful hints/help that could get me move > ahead. > > Thanks, I've defined a second delegate with a signature identical to your Integrate method. Does that help? Test2 is the meat and veg. using System; namespace RunLotsOfThreads2 { public class Integral { public delegate double DlgFn(double x); public delegate double DlgFn2(DlgFn f, double a, double b, int n); public static double f1(double x) { return Math.Exp(-(x * x)); //function to be integrated by Simpson's rule } public static double Integrate(DlgFn f, double a, double b, int n) { double h = (b - a) / n;//step_size double sum = 0; sum += f(a) + f(b); for (int i = 1; i <= (n - 1); i += 2) sum += 4 * f(a + i * h); for (int i = 2; i <= (n - 1); i += 2) sum += 2 * f(a + i * h); return Math.Round((h / 3) * sum, 5); } public static void test() { string strResult = Integral.Integrate(new DlgFn(f1), 0, 1, 100).ToString(); Console.WriteLine(strResult); } public static void test2() { double lLim= 0; double uLim= 1; int n =100; // step no. DlgFn2 myFn = new DlgFn2(Integral.Integrate); string strResult =myFn(new DlgFn(Integral.f1), lLim, uLim, n).ToString(); Console.WriteLine(strResult); } } }
Still can't grasp why two delegates? The code should somehow be more crisp.
As I am newbie to using delegates, I was having hard time. But your code did solve my problem and so did help me move ahead for now. Many thanks ! [quoted text, click to view] "DeveloperX" <nntpDev@operamail.com> wrote in message news:1178713562.608062.91280@y5g2000hsa.googlegroups.com... > On 9 May, 03:20, "ASP.NET explorer" <aspdotnet@learner> wrote: >> The following piece of code (between comment /***************/ >> line )works >> fine. You can test is in console/win form/web page. Just print strResult. >> >> /**************************************************/ >> public delegate double DlgFn(double x); >> >> public static double f1(double x) { >> return Math.Exp(-(x * x)); //function to be integrated by >> Simpson's >> rule >> } >> public class Integral { >> public static double Integrate(DlgFn f, double a, double b, int >> n) { >> double h = (b - a) / n;//step_size >> double sum = 0; >> sum += f(a) + f(b); >> for (int i = 1; i <= (n - 1); i += 2) sum += 4 * f(a + i * >> h); >> for (int i = 2; i <= (n - 1); i += 2) sum += 2 * f(a + i * >> h); >> return Math.Round((h / 3) * sum, 5); >> } >> } >> string strResult = Integral.Integrate(new DlgFn(f1), 0, 1, >> 100).ToString(); >> /**************************************************/ >> >> However it does not enable me to extend my application further. >> >> I want to replace the last line of code, >> string strResult = Integral.Integrate(new DlgFn(f1), 0, 1, >> 100).ToString(); >> with the following lines: >> >> double lLim= 0; double uLim= 1; >> double n =100; // step no. >> DlgFn myFn = new DlgFn(Integral.Integrate); >> string strResult =myFn(f1, lLim, uLim, new).ToString(); >> >> The reason for doing so is because the variables, lLim, uLim and n will >> be >> used in other methods in application code. >> >> I eagerly look forward for any useful hints/help that could get me move >> ahead. >> >> Thanks, > > I've defined a second delegate with a signature identical to your > Integrate method. Does that help? Test2 is the meat and veg. > > using System; > namespace RunLotsOfThreads2 > { > public class Integral > { > public delegate double DlgFn(double x); > public delegate double DlgFn2(DlgFn f, double a, double b, int n); > > public static double f1(double x) > { > return Math.Exp(-(x * x)); //function to be integrated by Simpson's > rule > } > > > public static double Integrate(DlgFn f, double a, double b, int n) > { > double h = (b - a) / n;//step_size > double sum = 0; > sum += f(a) + f(b); > for (int i = 1; i <= (n - 1); i += 2) sum += 4 * f(a + i * h); > for (int i = 2; i <= (n - 1); i += 2) sum += 2 * f(a + i * h); > return Math.Round((h / 3) * sum, 5); > } > public static void test() > { > string strResult = Integral.Integrate(new DlgFn(f1), 0, 1, > 100).ToString(); > Console.WriteLine(strResult); > } > public static void test2() > { > double lLim= 0; double uLim= 1; > int n =100; // step no. > DlgFn2 myFn = new DlgFn2(Integral.Integrate); > string strResult =myFn(new DlgFn(Integral.f1), lLim, uLim, > n).ToString(); > Console.WriteLine(strResult); > } > } > } >
On Wed, 09 May 2007 16:10:15 -0700, ASP.NET explorer <aspdotnet@learner>
[quoted text, click to view] wrote: > Still can't grasp why two delegates? The code should somehow be more > crisp. I admit, I'm not really clear on what issue it is you're trying to solve. But if the reply from DeveloperX solved it, perhaps it really was as simple as having to declare a second delegate type. If so, then the answer to "why two delegates" is that the delegate type requires that the "signature" of the method used to create the new delegate matches exactly with that declared in the delegate type. The "signature" being things like the return value and the parameter list. You can't use the first delegate type you declared with any method except one that returns a double and takes exactly one double as a parameter. If you want to wrap the Integrate() method in a delegate, you need a new delegate type that matches *that* method's signature (returns a double, takes as parameters one DlgFn delegate, two doubles, and an int). If you still have questions, perhaps you could try to be a little more clear about how it is you want the code to work and why it is the code you've already got doesn't do what you want.
[quoted text, click to view]
"ASP.NET explorer" <aspdotnet@learner> wrote in message <snip>news:OWpFYCekHHA.4596@TK2MSFTNGP05.phx.gbl... public static double Integrate(DlgFn f, double a, double b, int n) > [quoted text, click to view] > I want to replace the last line of code, > string strResult = Integral.Integrate(new DlgFn(f1), 0, 1, > 100).ToString(); > with the following lines: > > double lLim= 0; double uLim= 1; > double n =100; // step no. > DlgFn myFn = new DlgFn(Integral.Integrate); > string strResult =myFn(f1, lLim, uLim, new).ToString(); I think you got all dyslexic when you slapped this together First you try to create a DlgFn out of Integral.Integrate which has the wrong signature. Then instead of passing myFn into Integrate you passed f1 to myFn Then you passed 'new' instead of 'n' as your last param Let me attempt to disentangle I assume that you meant some thing like this DlgFn myFn = new DlgFn(f1) string strResult =Integral.Integrate(myFn , lLim, uLim, n).ToString(); but that has a problem as well. The last param to Integrate takes an int and you are passing a double. So here we go again DlgFn myFn = new DlgFn(f1) string strResult =Integral.Integrate(myFn , lLim, uLim, (int)n).ToString(); Is that what you were looking for? Bill
Hi Bill,
A belated thanks for suggestions. All of you put me on right path and I am moving ahead with some knowledge. ---- [quoted text, click to view] "Bill Butler" <qwerty@asdf.com> wrote in message news:y9Q0i.22018$pW5.3871@trnddc07... > "ASP.NET explorer" <aspdotnet@learner> wrote in message > news:OWpFYCekHHA.4596@TK2MSFTNGP05.phx.gbl... > <snip> > public static double Integrate(DlgFn f, double a, double b, int n) > >> I want to replace the last line of code, >> string strResult = Integral.Integrate(new DlgFn(f1), 0, 1, >> 100).ToString(); >> with the following lines: >> >> double lLim= 0; double uLim= 1; >> double n =100; // step no. >> DlgFn myFn = new DlgFn(Integral.Integrate); >> string strResult =myFn(f1, lLim, uLim, new).ToString(); > > I think you got all dyslexic when you slapped this together > > First you try to create a DlgFn out of Integral.Integrate which has the > wrong signature. > Then instead of passing myFn into Integrate you passed f1 to myFn > Then you passed 'new' instead of 'n' as your last param > > Let me attempt to disentangle > > I assume that you meant some thing like this > DlgFn myFn = new DlgFn(f1) > string strResult =Integral.Integrate(myFn , lLim, uLim, n).ToString(); > > but that has a problem as well. > The last param to Integrate takes an int and you are passing a double. > So here we go again > > DlgFn myFn = new DlgFn(f1) > string strResult =Integral.Integrate(myFn , lLim, uLim, > (int)n).ToString(); > > Is that what you were looking for? > > Bill >
Don't see what you're looking for? Try a search.
|
June 2003
July 2003
August 2003
September 2003
October 2003
November 2003
December 2003
January 2004
February 2004
March 2004
April 2004
May 2004
June 2004
July 2004
August 2004
September 2004
October 2004
November 2004
December 2004
January 2005
February 2005
March 2005
April 2005
May 2005
June 2005
July 2005
August 2005
September 2005
October 2005
November 2005
December 2005
January 2006
February 2006
March 2006
April 2006
May 2006
June 2006
July 2006
August 2006
September 2006
October 2006
November 2006
December 2006
January 2007
February 2007
March 2007
April 2007
May 2007
June 2007
July 2007
August 2007
September 2007
October 2007
November 2007
December 2007
January 2008
February 2008
March 2008
April 2008
| home · blog · groups | Questions? Comments? Contact the dn |