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  • How do I alias the scala setter method 'myvar_$(myval)' to something more pleasing when in java?

    - by feydr
    I've been converting some code from java to scala lately trying to tech myself the language. Suppose we have this scala class: class Person() { var name:String = "joebob" } Now I want to access it from java so I can't use dot-notation like I would if I was in scala. So I can get my var's contents by issuing: person = Person.new(); System.out.println(person.name()); and set it via: person = Person.new(); person.name_$eq("sallysue"); System.out.println(person.name()); This holds true cause our Person Class looks like this in javap: Compiled from "Person.scala" public class Person extends java.lang.Object implements scala.ScalaObject{ public Person(); public void name_$eq(java.lang.String); public java.lang.String name(); public int $tag() throws java.rmi.RemoteException; } Yes, I could write my own getters/setters but I hate filling classes up with that and it doesn't make a ton of sense considering I already have them -- I just want to alias the _$eq method better. (This actually gets worse when you are dealing with stuff like antlr because then you have to escape it and it ends up looking like person.name_\$eq("newname"); Note: I'd much rather have to put up with this rather than fill my classes with more setter methods. So what would you do in this situation?

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  • What is the nicest way to parse this in C++ ?

    - by ereOn
    Hi, In my program, I have a list of "server address" in the following format: host[:port] The brackets here, indicate that the port is optional. host can be a hostname, an IPv4 or IPv6 address. port, if present can be a numeric port number or a service string (like: "http" or "ssh"). If port is present and host is an IPv6 address, host must be in "bracket-enclosed" notation (Example: [::1]) Here are some valid examples: localhost localhost:11211 127.0.0.1:http [::1]:11211 ::1 [::1] And an invalid example: ::1:80 // Invalid: Is this the IPv6 address ::1:80 and a default port, or the IPv6 address ::1 and the port 80 ? ::1:http // This is not ambigous, but for simplicity sake, let's consider this is forbidden as well. My goal is to separate such entries in two parts (obviously host and port). I don't care if either the host or port are invalid as long as they don't contain a : (290.234.34.34.5 is ok for host, it will be rejected in the next process); I just want to separate the two parts, or if there is no port part, to know it somehow. I tried to do something with std::stringstream but everything I come up to seems hacky and not really elegant. How would you do this in C++ ? I don't mind answers in C but C++ is prefered. Any boost solution is welcome as well. Thank you.

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  • How can I solve the Log Pile wooden puzzle with a computer program?

    - by craig1410
    Can anyone suggest how to solve the Log Pile wooden puzzle using a computer program? See here to visualise the puzzle: http://www.puzzlethis.co.uk/products/madcow/the_log_pile.htm The picture only shows some of the pieces. The full set of 10 pieces are configured as follows with 1 representing a peg, -1 representing a hole and 0 representing neither a peg nor a hole. -1,1,0,-1,0 1,0,1,0,0 1,-1,1,0,0 -1,-1,0,0,-1 -1,1,0,1,0 0,1,0,0,1 1,0,-1,0,-1 0,-1,0,1,0 0,0,-1,1,-1 1,0,-1,0,0 The pieces can be interlocked in two layers of 5 pieces each with the top layer at 90 degrees to the bottom layer as shown in the above link. I have already created a solution to this problem myself using Java but I feel that it was a clumsy solution and I am interested to see some more sophisticated solutions. Feel free to either suggest a general approach or to provide a working program in the language of your choice. My approach was to use the numeric notation above to create an array of "Logs". I then used a combination/permutation generator to try all possible arrangements of the Logs until a solution was found where all the intersections equated to zero (ie. Peg to Hole, Hole to Peg or Blank to Blank). I used some speed-ups to detect the first failed intersection for a given permutation and move on to the next permutation. I hope you find this as interesting as I have. Thanks, Craig.

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  • How do I alias the scala setter method 'myvar_$eq(myval)' to something more pleasing when in java?

    - by feydr
    I've been converting some code from java to scala lately trying to teach myself the language. Suppose we have this scala class: class Person() { var name:String = "joebob" } Now I want to access it from java so I can't use dot-notation like I would if I was in scala. So I can get my var's contents by issuing: person = Person.new(); System.out.println(person.name()); and set it via: person = Person.new(); person.name_$eq("sallysue"); System.out.println(person.name()); This holds true cause our Person Class looks like this in javap: Compiled from "Person.scala" public class Person extends java.lang.Object implements scala.ScalaObject{ public Person(); public void name_$eq(java.lang.String); public java.lang.String name(); public int $tag() throws java.rmi.RemoteException; } Yes, I could write my own getters/setters but I hate filling classes up with that and it doesn't make a ton of sense considering I already have them -- I just want to alias the _$eq method better. (This actually gets worse when you are dealing with stuff like antlr because then you have to escape it and it ends up looking like person.name_\$eq("newname"); Note: I'd much rather have to put up with this rather than fill my classes with more setter methods. So what would you do in this situation?

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  • Extended slice that goes to beginning of sequence with negative stride

    - by recursive
    Bear with me while I explain my question. Skip down to the bold heading if you already understand extended slice list indexing. In python, you can index lists using slice notation. Here's an example: >>> A = list(range(10)) >>> A[0:5] [0, 1, 2, 3, 4] You can also include a stride, which acts like a "step": >>> A[0:5:2] [0, 2, 4] The stride is also allowed to be negative, meaning the elements are retrieved in reverse order: >>> A[5:0:-1] [5, 4, 3, 2, 1] But wait! I wanted to see [4, 3, 2, 1, 0]. Oh, I see, I need to decrement the start and end indices: >>> A[4:-1:-1] [] What happened? It's interpreting -1 as being at the end of the array, not the beginning. I know you can achieve this as follows: >>> A[4::-1] [4, 3, 2, 1, 0] But you can't use this in all cases. For example, in a method that's been passed indices. My question is: Is there any good pythonic way of using extended slices with negative strides and explicit start and end indices that include the first element of a sequence? This is what I've come up with so far, but it seems unsatisfying. >>> A[0:5][::-1] [4, 3, 2, 1, 0]

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  • Pre-done SQLs to be converted to Rails' style moduls

    - by Hoornet
    I am a Rails newbie and would really appreciate if someone converted these SQLs to complete modules for rails. I know its a lot to ask but I can't just use find_by_sql for all of them. Or can I? These are the SQLs (they run on MS-SQL): 1) SELECT STANJA_NA_DAN_POSTAVKA.STA_ID, STP_DATE, STP_TIME, STA_OPIS, STA_SIFRA, STA_POND FROM STANJA_NA_DAN_POSTAVKA INNER JOIN STANJA_NA_DAN ON(STANJA_NA_DAN.STA_ID=STANJA_NA_DAN_POSTAVKA.STA_ID) WHERE ((OSE_ID=10)AND (STANJA_NA_DAN_POSTAVKA.STP_DATE={d '2010-03-30'}) AND (STANJA_NA_DAN_POSTAVKA.STP_DATE<={d '2010-03-30'})) 2) SELECT ZIGI_OBDELANI.OSE_ID, ZIGI_OBDELANI.DOG_ID AS DOG_ID, ZIGI_OBDELANI.ZIO_DATUM AS DATUM, ZIGI_PRICETEK.ZIG_TIME_D AS ZIG_PRICETEK, ZIGI_KONEC.ZIG_TIME_D AS ZIG_KONEC FROM (ZIGI_OBDELANI INNER JOIN ZIGI ZIGI_PRICETEK ON ZIGI_OBDELANI.ZIG_ID_PRICETEK = ZIGI_PRICETEK.ZIG_ID) INNER JOIN ZIGI ZIGI_KONEC ON ZIGI_OBDELANI.ZIG_ID_KONEC = ZIGI_KONEC.ZIG_ID WHERE (ZIGI_OBDELANI.OSE_ID = 10) AND (ZIGI_OBDELANI.ZIO_DATUM = {d '2010-03-30'}) AND (ZIGI_OBDELANI.ZIO_DATUM <= {d '2010-03-30'}) AND (ZIGI_PRICETEK.ZIG_VELJAVEN < 0) AND (ZIGI_KONEC.ZIG_VELJAVEN < 0) ORDER BY ZIGI_OBDELANI.OSE_ID, ZIGI_PRICETEK.ZIG_TIME ASC 3) SELECT STA_ID, SUM(STP_TIME) AS SUM_STP_TIME, COUNT(STA_ID) FROM STANJA_NA_DAN_POSTAVKA WHERE ((STP_DATE={d '2010-03-30'}) AND (STP_DATE<={d '2010-03-30'}) AND (STA_ID=3) AND (OSE_ID=10)) GROUP BY STA_ID 4) SELECT DATUM, TDN_ID, TDN_OPIS, URN_OPIS, MOZNI_PROBLEMI, PRIHOD, ODHOD, OBVEZNOST, ZAKLJUCEVANJE_DATUM FROM OBRACUNAJ_DAN WHERE ((OSE_ID=10) AND (DATUM={d '2010-02-28'}) AND (DATUM<={d '2010-03-30'})) ORDER BY DATUM These SQLs are daily working hours and I got them as is. Also I got Database with it which (as you can see from the SQL-s) is not in Rails conventions. As a P.S.: 1)Things like STP_DATE={d '2010-03-30'}) are of course dates (in Slovenian date notation) and will be replaced with a variable (date), so that the user could choose date from and date to. 2) All of this data will be shown in the same page in the table,so maybe all in one module? Or many?; if this helps, maybe. So can someone help me? Its for my work and its my 1st project and I am a Rails newbie and the bosses are getting inpatient(they are getting quite loud actually) Thank you very very much!

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  • Code casing question for private class fields

    - by user200295
    Take the following example public class Class1{ public string Prop1{ get {return m_Prop1;} set {m_Prop1 = value; } } private string m_Prop1; // this is standard private property variable name // how do we cap this variable name? While the compiler can figure out same casing // it makes it hard to read private Class2 Class2; // we camel case the parameter public Class1(Class2 class2){ this.Class2 = class2; } } Here are my stock rules The class name is capitalized (Class1) The public properties are capitalized (Prop1) The private field tied to a public property has m_ to indicate this. My coworker prefers _ There is some debate if using m_ or _ should be used at all, as it is like Hungarian notation. Private class fields are capitalized. The part I am trying to figure out is what do I do if when the Class name of a private field matches the private field name. For example, private Class2 Class2; This is confusing. If the private field name is not the same class, for example private string Name; , there isn't much issue. Or am I thinking about the issue wrong. Should my classes and private fields be named in such a way that they don't collide?

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  • "for" loop from program 7.6 from Kochan's "Programming in Objective-C"

    - by Mr_Vlasov
    "The sigma notation is shorthand for a summation. Its use here means to add the values of 1/2^i, where i varies from 1 to n. That is, add 1/2 + 1/4 + 1/8 .... If you make the value of n large enough, the sum of this series should approach 1. Let’s experiment with different values for n to see how close we get." #import "Fraction.h" int main (int argc, char *argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; Fraction *aFraction = [[Fraction alloc] init]; Fraction *sum = [[Fraction alloc] init], *sum2; int i, n, pow2; [sum setTo: 0 over: 1]; // set 1st fraction to 0 NSLog (@"Enter your value for n:"); scanf ("%i", &n); pow2 = 2; for (i = 1; i <= n; ++i) { [aFraction setTo: 1 over: pow2]; sum2 = [sum add: aFraction]; [sum release]; // release previous sum sum = sum2; pow2 *= 2; } NSLog (@"After %i iterations, the sum is %g", n, [sum convertToNum]); [aFraction release]; [sum release]; [pool drain]; return 0; } Question: Why do we have to create additional variable sum2 that we are using in the "for" loop? Why do we need "release previous sum" here and then again give it a value that we just released? : sum2 = [sum add: aFraction]; [sum release]; // release previous sum sum = sum2; Is it just for the sake of avoiding memory leakage? (method "add" initializes a variable that is stored in sum2)

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  • templated method on T inside a templated class on TT : Is that possible/correct.

    - by paercebal
    I have a class MyClass which is templated on typename T. But inside, I want a method which is templated on another type TT (which is unrelated to T). After reading/tinkering, I found the following notation: template <typename T> class MyClass { public : template<typename TT> void MyMethod(const TT & param) ; } ; For stylistic reasons (I like to have my templated class declaration in one header file, and the method definitions in another header file), I won't define the method inside the class declaration. So, I have to write it as: template <typename T> // this is the type of the class template <typename TT> // this is the type of the method void MyClass<T>::MyMethod(const TT & param) { // etc. } I knew I had to "declare" the typenames used in the method, but didn't know how exactly, and found through trials and errors. The code above compiles on Visual C++ 2008, but: Is this the correct way to have a method templated on TT inside a class templated on T? As a bonus: Are there hidden problems/surprises/constraints behind this kind of code? (I guess the specializations can be quite amusing to write)

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  • Weird behaviour with Scanner#nextFloat

    - by James P.
    Running the following in Eclipse initially caused Scanner to not recognize carriage returns in the console effectively blocking further input: price = sc.nextFloat(); Adding this line before the code causes Scanner to accept 0,23 (french notation) as a float: Locale.setDefault(Locale.US); This is most probably due to regional settings in Windows XP Pro. When the code is run again 0,23 is still accepted and entering 0.23 causes it to throw a java.util.InputMismatchException. Any explanation as to why this is happening? Also is there a workaround or should I just use Float#parseFloat? Edit: import java.util.Locale; import java.util.Scanner; public class NexFloatTest { public static void main(String[] args) { //Locale.setDefault(Locale.US); //Locale.setDefault(Locale.FRANCE); // Gives fr_BE on this system System.out.println(Locale.getDefault()); float price; String uSDecimal = "0.23"; String frenchDecimal = "0,23"; Scanner sc = new Scanner(uSDecimal); try{ price = sc.nextFloat(); System.out.println(price); } catch (java.util.InputMismatchException e){ e.printStackTrace(); } try{ sc = new Scanner(frenchDecimal); price = sc.nextFloat(); System.out.println(price); } catch (java.util.InputMismatchException e){ e.printStackTrace(); } String title = null; System.out.print("Enter title:"); try{ title = sc.nextLine(); // This line is skippe } catch(java.util.NoSuchElementException e ){ e.printStackTrace(); } System.out.print(title); } }

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  • How to achieve to following C++ output formatting?

    - by Yan Cheng CHEOK
    I wish to print out double as the following rules : 1) No scietific notation 2) Maximum decimal point is 3 3) No trailing 0. For example : 0.01 formated to "0.01" 2.123411 formatted to "2.123" 2.11 formatted to "2.11" 2.1 formatted to "2.1" 0 formatted to "0" By using .precision(3) and std::fixed, I can only achieve rule 1) and rule 2), but not rule 3) 0.01 formated to "0.010" 2.123411 formatted to "2.123" 2.11 formatted to "2.110" 2.1 formatted to "2.100" 0 formatted to "0" Code example is as bellow : #include <iostream> int main() { std::cout.precision(3); std::cout << std::fixed << 0.01 << std::endl; std::cout << std::fixed << 2.123411 << std::endl; std::cout << std::fixed << 2.11 << std::endl; std::cout << std::fixed << 2.1 << std::endl; std::cout << std::fixed << 0 << std::endl; getchar(); } any idea?

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  • Risky Business with LINQ to SQL and OR Designer?

    - by Toadmyster
    I have two tables with a one to many relationship in SQL 2008. The first table (BBD) PK | BBDataID | int       | Floor_Qty | tinyint       | Construct_Year | char(4)       | etc, etc describes the data common to all buildings and the second (BBDCerts) PK | BBDCertsID | int       | BBDataID | int       | Certification_Type | varchar(20)       | etc, etc is a collection of certifications for a particular building. Thus, the primary key in BBD (BBDataID) is mapped to the corresponding field in BBDCerts via an FK relationship, but BBDCertsID is the second table's primary key and BBDataID is not because it will not be unique. My problem is that I want to be able to use the OR generated data context to get at the list of certs when I access a particular record in the BBD table. For instance: Dim vals = (From q in db.BBD Where q.BBDataID = x Select q.Floor_Qty, q.Construct_Year, q.BBDCerts).SingleOrDefault and later be able to access a particular certification like this: vals.BBDCerts.Certification_Type.First Now, the automatic associations created when the SQL tables are dropped on the design surface don't generate the EntityRef associations that are needed to access the other table using the dot notation. So, I have to use the OR designer to make the BBDCerts BBDataID a primary key (this doesn't affect the actual database), and then manually change the association properties to the appropriate OneToMany settings. There might be a better way to approach this solution but my question is, is the way I've done it safe? I've done a barrage of tests and the correct cert is referenced or updated every time. Frankly, the whole thing makes me nervous.

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  • Fill lower matrix with vector by row, not column

    - by mhermans
    I am trying to read in a variance-covariance matrix written out by LISREL in the following format in a plain text, whitespace separated file: 0.23675E+01 0.86752E+00 0.28675E+01 -0.36190E+00 -0.36190E+00 0.25381E+01 -0.32571E+00 -0.32571E+00 0.84425E+00 0.25598E+01 -0.37680E+00 -0.37680E+00 0.53136E+00 0.47822E+00 0.21120E+01 -0.37680E+00 -0.37680E+00 0.53136E+00 0.47822E+00 0.91200E+00 0.21120E+01 This is actually a lower diagonal matrix (including diagonal): 0.23675E+01 0.86752E+00 0.28675E+01 -0.36190E+00 -0.36190E+00 0.25381E+01 -0.32571E+00 -0.32571E+00 0.84425E+00 0.25598E+01 -0.37680E+00 -0.37680E+00 0.53136E+00 0.47822E+00 0.21120E+01 -0.37680E+00 -0.37680E+00 0.53136E+00 0.47822E+00 0.91200E+00 0.21120E+01 I can read in the values correctly with scan() or read.table(fill=T). I am however not able to correctly store the read-in vector in a matrix. The following code S <- diag(6) S[lower.tri(S,diag=T)] <- d fills the lower matrix by column, while it should fill it by row. Using matrix() does allow for the option byrow=TRUE, but this will fill in the whole matrix, not just the lower half (with diagonal). Is it possible to have both: only fill the lower matrix (with diagonal) and do it by row? (separate issue I'm having: LISREL uses 'D+01' while R only recognises 'E+01' for scientific notation. Can you change this in R to accept also 'D'?)

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  • Show a number with specified number of significant digits

    - by dreeves
    I use the following function to convert a number to a string for display purposes (don't use scientific notation, don't use a trailing dot, round as specified): (* Show Number. Convert to string w/ no trailing dot. Round to the nearest r. *) Unprotect[Round]; Round[x_,0] := x; Protect[Round]; shn[x_, r_:0] := StringReplace[ ToString@NumberForm[Round[N@x,r], ExponentFunction->(Null&)], re@"\\.$"->""] (Note that re is an alias for RegularExpression.) That's been serving me well for years. But sometimes I don't want to specify the number of digits to round to, rather I want to specify a number of significant figures. For example, 123.456 should display as 123.5 but 0.00123456 should display as 0.001235. To get really fancy, I might want to specify significant digits both before and after the decimal point. For example, I might want .789 to display as 0.8 but 789.0 to display as 789 rather than 800. Do you have a handy utility function for this sort of thing, or suggestions for generalizing my function above? Related: Suppressing a trailing "." in numerical output from Mathematica

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  • What is the n in O(n) when comparing sorting algorithms?

    - by Mumfi
    The question is rather simple, but I just can't find a good enough answer. I've taken a look at the most upvoted question regarding the Big-Oh notation, namely this: Plain English explanation of Big O It says there that: For example, sorting algorithms are typically compared based on comparison operations (comparing two nodes to determine their relative ordering). Now let's consider the simple bubble sort algorithm: for (int i = arr.length - 1; i > 0 ; i--) { for (int j = 0; j<i; j++) { if (arr[j] > arr[j+1]) { switchPlaces(...) } } } I know that worst case is O(n^2) and best case is O(n), but what is n exactly? If we attempt to sort an already sorted algorithm (best case), we would end up doing nothing, so why is it still O(n)? We are looping through 2 for-loops still, so if anything it should be O(n^2). n can't be the number of comparison operations, because we still compare all the elements, right? This confuses me, and I appreciate if someone could help me.

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  • Common block usage in Fortran

    - by Crystal
    I'm new to Fortran and just doing some simple things for work. And as a new programmer in general, not sure exactly how this works, so excuse me if my explanation or notation is not the best. At the top of the .F file there are common declarations. The person explaining it to me said think of it like a struct in C, and that they are global. Also in that same .F file, they have it declared with what type. So it's something like: COMMON SOMEVAR INTEGER*2 SOMEVAR And then when I actually see it being used in some other file, they declare local variables, (e.g. SOMEVAR_LOCAL) and depending on the condition, they set SOMEVAR_LOCAL = 1 or 0. Then there is another conditional later down the line that will say something like IF (SOMEVAR_LOCAL. eq. 1) SOMEVAR(PARAM) = 1; (Again I apologize if this is not proper Fortran, but I don't have access to the code right now). So it seems to me that there is a "struct" like variable called SOMEVAR that is of some length (2 bytes of data?), then there is a local variable that is used as a flag so that later down the line, the global struct SOMEVAR can be set to that value. But because there is (PARAM), it's like an array for that particular instance? Thanks. Sorry for my bad explanation, but hopefully you will understand what I am asking.

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  • Big-Oh running time of code in Java (are my answers accurate

    - by Terry Frederick
    the Method hasTwoTrueValues returns true if at least two values in an array of booleans are true. Provide the Big-Oh running time for all three implementations proposed. // Version 1 public boolean has TwoTrueValues( boolean [ ] arr ) { int count = 0; for( int i = 0; i < arr. length; i++ ) if( arr[ i ] ) count++; return count >= 2; } // Version 2 public boolean hasTwoTrueValues( boolean [ ] arr ) { for( int i = 0; i < arr.length; i++ ) for( int j = i + 1; j < arr.length; j++ ) if( arr[ i ] && arr[ j ] ) return true; } // Version 3 public boolean hasTwoTrueValues( boolean [ ] arr ) { for( int i = 0; i < arr.length; i++ if( arr[ i ] ) for( int j = i + 1; j < arr.length; j++ ) if( arr[ j ] ) return true; return false; } For Version 1 I say the running time is O(n) Version 2 I say O(n^2) Version 3 I say O(n^2) I am really new to this Big Oh Notation so if my answers are incorrect could you please explain and help.

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  • Is there such a thing as a MemberExpression that handles a many-to-many relationship?

    - by Jaxidian
    We're trying to make it easy to write strongly-typed code in all areas of our system, so rather than setting var sortColumn = "FirstName" we'd like to say sortOption = (p => p.FirstName). This works great if the sortOption is of type Expression<Func<Person, object>> (we actually use generics in our code but that doesn't matter). However, we run into problems for many-to-many relationships because this notation breaks down. Consider this simple code: internal class Business { public IQueryable<Address> Addresses { get; set; } public string Name { get; set; } } internal class Address { public State MyState { get; set; } } internal class State { public string Abbreviation { get; set; } public int StateID { get; set; } } Is it possible to have this sort of MemberExpression to identify the StateID column off of a business? Again, the purpose of using this is not to return a StateID object, it's to just identify that property off of that entity (for sorting, filtering, and other purposes). It SEEMS to me that there should be some way to do this, even if it's not quite as pretty as foo = business.Addresses.SomeExtension(a => a.State.StateID);. Is this really possible? If more background is needed, take a look at this old question of mine. We've since updated the code significantly, but this should give you the general detailed idea of the context behind this question.

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  • Implement two functions with the same name but different, non-covariant return types due to multiple abstract base classes

    - by user1508167
    If I have two abstract classes defining a pure virtual function with the same name, but different, non-covariant return types, how can I derive from these and define an implementation for both their functions? #include <iostream> class ITestA { public: virtual ~ITestA() {}; virtual float test() =0; }; class ITestB { public: virtual ~ITestB() {}; virtual bool test() =0; }; class C : public ITestA, public ITestB { public: /* Somehow implement ITestA::test and ITestB::test */ }; int main() { ITestA *a = new C(); std::cout << a->test() << std::endl; // should print a float, like "3.14" ITestB *b = dynamic_cast<ITestB *>(a); if (b) { std::cout << b->test() << std::endl; // should print "1" or "0" } delete(a); return 0; } As long as I don't call C::test() directly there's nothing ambiguous, so I think that it should work somehow and I guess I just didn't find the right notation yet. Or is this impossible, if so: Why?

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  • format, iomanip, c++

    - by Crystal
    I'm trying to learn to use namespaces declarations more definitive than not just say "using namespace std". I'm trying to format my data to 2 decimal places, and set the format to be fixed and not scientific. This is my main file: #include <iostream> #include <iomanip> #include "SavingsAccount.h" using std::cout; using std::setprecision; using std::ios_base; int main() { SavingsAccount *saver1 = new SavingsAccount(2000.00); SavingsAccount *saver2 = new SavingsAccount(3000.00); SavingsAccount::modifyInterestRate(.03); saver1->calculateMonthlyInterest(); saver2->calculateMonthlyInterest(); cout << ios_base::fixed << "saver1\n" << "monthlyInterestRate: " << saver1->getMonthlyInterest() << '\n' << "savingsBalance: " << saver1->getSavingsBalance() << '\n'; cout << "saver2\n" << "monthlyInterestRate: " << saver2->getMonthlyInterest() << '\n' << "savingsBalance: " << saver2->getSavingsBalance() << '\n'; } On Visual Studio 2008, when I run my program, I get an output of "8192" before the data I want. Is there a reason for that? Also, I don't think I am setting the fixed part or 2 decimal places correctly since I seem to get scientific notation once I added the setprecision(2). Thanks.

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  • Runtime of optimized Primehunter

    - by Setton
    Ok so I need some serious runtime help here! This method should take in an int value, check its primality, and return true if the number is indeed a prime. I understand why the loop only needs to go up to i squared, I understand that the worst case scenario is the case in which either the number is prime (or a multiple of a prime). But I don't understand how to quantify the actual runtime. I have done the loop myself by hand to try to understand the pattern or correlation of the number (n) and how many loops occur, but I literally feel like I keep falling into the same trap every time. I need a new way of thinking about this! I have a hint: "Think about the SIZE of the integer" which makes me want to quantify the literal number of integers in a number in relation to how many iterations it does in the for loop (floor log(n)) +1). BUT IT'S NOT WORKIIIING?! I KNOW it isn't square root n, obviously. I'm asking for Big O notation. public class PrimeHunter { public static boolean isPrime(int n) { boolean answer = (n > 1) ? true : false; //runtime = linear runtime for (int i = 2; i * i <= n; i++) //runtime = ????? { if (n % i == 0) //doesn't occur if it is a prime { answer = false; break; } } return answer; //runtime = linear runtime } }

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  • ActionResult types in MVC2

    - by rajbk
    In ASP.NET MVC, incoming browser requests gets mapped to a controller action method. The action method returns a type of ActionResult in response to the browser request. A basic example is shown below: public class HomeController : Controller { public ActionResult Index() { return View(); } } Here we have an action method called Index that returns an ActionResult. Inside the method we call the View() method on the base Controller. The View() method, as you will see shortly, is a method that returns a ViewResult. The ActionResult class is the base class for different controller results. The following diagram shows the types derived from the ActionResult type. ASP.NET has a description of these methods ContentResult – Represents a text result. EmptyResult – Represents no result. FileContentResult – Represents a downloadable file (with the binary content). FilePathResult – Represents a downloadable file (with a path). FileStreamResult – Represents a downloadable file (with a file stream). JavaScriptResult – Represents a JavaScript script. JsonResult – Represents a JavaScript Object Notation result that can be used in an AJAX application. PartialViewResult – Represents HTML and markup rendered by a partial view. RedirectResult – Represents a redirection to a new URL. RedirectToRouteResult – Represents a result that performs a redirection by using the specified route values dictionary. ViewResult – Represents HTML and markup rendered by a view. To return the types shown above, you call methods that are available in the Controller base class. A list of these methods are shown below.   Methods without an ActionResult return type The MVC framework will translate action methods that do not return an ActionResult into one. Consider the HomeController below which has methods that do not return any ActionResult types. The methods defined return an int, object and void respectfully. public class HomeController : Controller { public int Add(int x, int y) { return x + y; }   public Employee GetEmployee() { return new Employee(); }   public void DoNothing() { } } When a request comes in, the Controller class hands internally uses a ControllerActionInvoker class which inspects the action parameters and invokes the correct action method. The CreateActionResult method in the ControllerActionInvoker class is used to return an ActionResult. This method is shown below. If the result of the action method is null, an EmptyResult instance is returned. If the result is not of type ActionResult, the result is converted to a string and returned as a ContentResult. protected virtual ActionResult CreateActionResult(ControllerContext controllerContext, ActionDescriptor actionDescriptor, object actionReturnValue) { if (actionReturnValue == null) { return new EmptyResult(); }   ActionResult actionResult = (actionReturnValue as ActionResult) ?? new ContentResult { Content = Convert.ToString(actionReturnValue, CultureInfo.InvariantCulture) }; return actionResult; }   In the HomeController class above, the DoNothing method will return an instance of the EmptyResult() Renders an empty webpage the GetEmployee() method will return a ContentResult which contains a string that represents the current object Renders the text “MyNameSpace.Controllers.Employee” without quotes. the Add method for a request of /home/add?x=3&y=5 returns a ContentResult Renders the text “8” without quotes. Unit Testing The nice thing about the ActionResult types is in unit testing the controller. We can, without starting a web server, create an instance of the Controller, call the methods and verify that the type returned is the expected ActionResult type. We can then inspect the returned type properties and confirm that it contains the expected values. Enjoy! Sulley: Hey, Mike, this might sound crazy but I don't think that kid's dangerous. Mike: Really? Well, in that case, let's keep it. I always wanted a pet that could kill me.

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  • Test and Report Add-on Compatibility in Firefox

    - by Asian Angel
    Now that the new version of Firefox is out you probably have a favorite extension or two that has not updated yet. You can get that extension working again, test it, and report back to Mozilla on how well it does with the Add-on Compatibility Reporter extension. Before For our example we chose a great extension that unfortunately has not been updated yet. As you can see here Firefox is refusing to let the extension install. After As soon as you install Add-on Compatibility Reporter you will be presented with an information page on how the extension works and what you can do with it. You should definitely take a moment to read this as it is very helpful. After trying our non-compatible extension again we were able to proceed with the install process. Notice at the bottom that “compatibility checking” has been overridden. Success! As soon as we restarted our browser it was easy to see the “non-compatible icon” in the “Add-ons Manager Window”…but the extension did install though (terrific!). Clicking on the extension’s entry will reveal a new button in the lower right corner. Using the “Compatibility Drop-Down Menu” you can report if the extension is working as well as before or if it is actually having problems. The extension that we used for our example had no problems whatsoever so good news there. Whichever option you choose you will be presented with a small “Report Window” with information about the extension, your browser’s version number, and your operating system. Click “Submit Report” to send it on its’ way. You will see a confirmation message letting you know that your report was successfully submitted. While the extension itself has not been altered in any form at least you have it working again and have helped verify whether it still works well or not. Notice the “notation” present now in place of the “Compatibility Button” that lets you know that you have already taken care of that particular extension. Looking great… Conclusion If you have a favorite extension that you miss using in the newest release of Firefox then this is definitely an extension to add to your browser. Not only will your extension start working again but you can let Mozilla know how well it is working and (hopefully) help get the extension updated. Links Download the Add-on Compatibility Reporter extension (Mozilla Add-ons) Similar Articles Productive Geek Tips Firefox 3.6 Release Candidate Available, Here’s How to Fix Your Incompatible ExtensionsUsing Windows 7 or Vista Compatibility ModeMysticgeek Blog: Generate A System Health Report In VistaCheck Extension Compatibility for Upcoming Firefox ReleasesMake Safari Stop Crashing Every 20 Seconds on Windows Vista TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 PCmover Professional Make your Joomla & Drupal Sites Mobile with OSMOBI Integrate Twitter and Delicious and Make Life Easier Design Your Web Pages Using the Golden Ratio Worldwide Growth of the Internet How to Find Your Mac Address Use My TextTools to Edit and Organize Text

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  • Big Data – Operational Databases Supporting Big Data – Key-Value Pair Databases and Document Databases – Day 13 of 21

    - by Pinal Dave
    In yesterday’s blog post we learned the importance of the Relational Database and NoSQL database in the Big Data Story. In this article we will understand the role of Key-Value Pair Databases and Document Databases Supporting Big Data Story. Now we will see a few of the examples of the operational databases. Relational Databases (Yesterday’s post) NoSQL Databases (Yesterday’s post) Key-Value Pair Databases (This post) Document Databases (This post) Columnar Databases (Tomorrow’s post) Graph Databases (Tomorrow’s post) Spatial Databases (Tomorrow’s post) Key Value Pair Databases Key Value Pair Databases are also known as KVP databases. A key is a field name and attribute, an identifier. The content of that field is its value, the data that is being identified and stored. They have a very simple implementation of NoSQL database concepts. They do not have schema hence they are very flexible as well as scalable. The disadvantages of Key Value Pair (KVP) database are that they do not follow ACID (Atomicity, Consistency, Isolation, Durability) properties. Additionally, it will require data architects to plan for data placement, replication as well as high availability. In KVP databases the data is stored as strings. Here is a simple example of how Key Value Database will look like: Key Value Name Pinal Dave Color Blue Twitter @pinaldave Name Nupur Dave Movie The Hero As the number of users grow in Key Value Pair databases it starts getting difficult to manage the entire database. As there is no specific schema or rules associated with the database, there are chances that database grows exponentially as well. It is very crucial to select the right Key Value Pair Database which offers an additional set of tools to manage the data and provides finer control over various business aspects of the same. Riak Rick is one of the most popular Key Value Database. It is known for its scalability and performance in high volume and velocity database. Additionally, it implements a mechanism for collection key and values which further helps to build manageable system. We will further discuss Riak in future blog posts. Key Value Databases are a good choice for social media, communities, caching layers for connecting other databases. In simpler words, whenever we required flexibility of the data storage keeping scalability in mind – KVP databases are good options to consider. Document Database There are two different kinds of document databases. 1) Full document Content (web pages, word docs etc) and 2) Storing Document Components for storage. The second types of the document database we are talking about over here. They use Javascript Object Notation (JSON) and Binary JSON for the structure of the documents. JSON is very easy to understand language and it is very easy to write for applications. There are two major structures of JSON used for Document Database – 1) Name Value Pairs and 2) Ordered List. MongoDB and CouchDB are two of the most popular Open Source NonRelational Document Database. MongoDB MongoDB databases are called collections. Each collection is build of documents and each document is composed of fields. MongoDB collections can be indexed for optimal performance. MongoDB ecosystem is highly available, supports query services as well as MapReduce. It is often used in high volume content management system. CouchDB CouchDB databases are composed of documents which consists fields and attachments (known as description). It supports ACID properties. The main attraction points of CouchDB are that it will continue to operate even though network connectivity is sketchy. Due to this nature CouchDB prefers local data storage. Document Database is a good choice of the database when users have to generate dynamic reports from elements which are changing very frequently. A good example of document usages is in real time analytics in social networking or content management system. Tomorrow In tomorrow’s blog post we will discuss about various other Operational Databases supporting Big Data. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • Inspiring a co-worker to adopt better coding practices?

    - by Aaronaught
    In the Handling my antiquated coworker question, various people discussed strategies for dealing with coworkers who are unwilling to integrate their workflow with the team's. I'd like, if possible, to learn some strategies for "teaching" a coworker who is merely ignorant of modern techniques and tools, and possibly a little apathetic. I've started working with a programmer who until recently has been working in relative isolation, in a different part of the company. He has extensive domain knowledge and most importantly he has demonstrated good problem-solving skills, something which many candidates seem to lack. However, the actual (C#) code I've seen is a throwback to the VB6 days. Procedural structure, Hungarian notation, global variables (abuse of static), no interfaces, no tests, non-use of Generics, throwing System.Exception... you get the idea. This programmer is a fair bit older than I am and, by first impressions at least, doesn't actively seek positive change. I'm not going to say resistant to change, because I think that is largely an issue of how the topic gets broached, and I want to be prepared. Programmers tend to be stubborn people, and going in with guns blazing and instituting rip-it-to-shreds code reviews and strictly-enforced policies is very likely not going to produce the end result that I want. If this were a new hire, a junior programmer, I wouldn't think twice about taking a "mentor" stance, but I'm extremely wary of treating an experienced employee as a clueless newbie (which he's not - he just hasn't kept pace with certain advancements in the field). How might I go about raising this developer's code quality standard the Dale Carnegie way, through gentle persuasion and non-material incentives? What would be the best strategy for effecting subtle, gradual changes, without creating an adversarial situation? Have other people - especially lead developers - been in this type of situation before? Which strategies were successful at stimulating interest and creating a positive group dynamic? Which strategies weren't successful and would be better to avoid? Clarifications: I really feel that several people are answering based on personal feelings without actually reading all of the details of the question. Please note the following, which should have been implied but I am now making explicit: This coworker is only my "senior" by virtue of age. I never said that his title, sphere of influence, or years at the organization exceed mine, and in fact, none of those things are true. He's a LOB programmer who's been absorbed into the main development shop. That's it. I am not a new hire, junior programmer, or other naïve idiot with grand plans to transform the company overnight. I am basically in charge of the software process, but as many who've worked as "leads" will know, responsibilities don't always correlate precisely with the org chart. I'm not asking people how to get my way, come hell or high water. I could do that if I wanted to, with the net result being that this person would become resentful and/or quit. Please try to understand that I am looking for a social, cooperative method of driving change. The mention of "...global variables... no tests... throwing System.Exception" was intended to demonstrate that the problems are not just superficial or aesthetic. Practices that may work for relatively small CRUD apps do not necessarily work for large enterprise apps, and in fact, none of the code so far has actually passed the integration tests. Please, try to take the question at face value, accept that I actually know what I'm talking about, and either answer the question that I actually asked or move on. P.S. My sincerest gratitude to those who -did- offer constructive advice rather than arguing with the premise. I'm going to leave this open for a while longer as I'm hoping to hear more in the way of real-world experiences.

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