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  3. So how well do you think you know C#?

So how well do you think you know C#?

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  • L leppie

    Rajesh R Subramanian wrote:

    How do you get formatted and colorised code like that? Is there a tool or something? Do you mind sharing it with me?

    xacc.ide*, select text, right click, copy special, copy to HTML :) * see link below

    xacc.ide - now with TabsToSpaces support
    IronScheme - 1.0 alpha 4a out now (29 May 2008)

    R Offline
    R Offline
    Rajesh R Subramanian
    wrote on last edited by
    #16

    It works with C++? Will I be able to specify a background color of my option? I know that I can modify the HTML, but I'm just asking. I'm downloading it at the moment. Thanks.

    Many are stubborn in pursuit of the path they have chosen, few in pursuit of the goal - Friedrich Nietzsche .·´¯`·->Rajesh<-·´¯`·. [Microsoft MVP - Visual C++]

    L 1 Reply Last reply
    0
    • R Rajesh R Subramanian

      It works with C++? Will I be able to specify a background color of my option? I know that I can modify the HTML, but I'm just asking. I'm downloading it at the moment. Thanks.

      Many are stubborn in pursuit of the path they have chosen, few in pursuit of the goal - Friedrich Nietzsche .·´¯`·->Rajesh<-·´¯`·. [Microsoft MVP - Visual C++]

      L Offline
      L Offline
      leppie
      wrote on last edited by
      #17

      Rajesh R Subramanian wrote:

      It works with C++?

      Not as nice as C#, but ok :)

      Rajesh R Subramanian wrote:

      Will I be able to specify a background color of my option? I know that I can modify the HTML, but I'm just asking.

      Nope, not IIRC, it just defaults to white, I cant remember if it picks up the color from the editor, or if that color can even be changed! Been very long since I wrote that :)

      xacc.ide - now with TabsToSpaces support
      IronScheme - 1.0 alpha 4a out now (29 May 2008)

      R 1 Reply Last reply
      0
      • L leppie

        Rajesh R Subramanian wrote:

        It works with C++?

        Not as nice as C#, but ok :)

        Rajesh R Subramanian wrote:

        Will I be able to specify a background color of my option? I know that I can modify the HTML, but I'm just asking.

        Nope, not IIRC, it just defaults to white, I cant remember if it picks up the color from the editor, or if that color can even be changed! Been very long since I wrote that :)

        xacc.ide - now with TabsToSpaces support
        IronScheme - 1.0 alpha 4a out now (29 May 2008)

        R Offline
        R Offline
        Rajesh R Subramanian
        wrote on last edited by
        #18

        I might give it a shot to add those features of my choice if time permits. I hardly work with C#. Thanks for the tool anyways.

        Many are stubborn in pursuit of the path they have chosen, few in pursuit of the goal - Friedrich Nietzsche .·´¯`·->Rajesh<-·´¯`·. [Microsoft MVP - Visual C++]

        1 Reply Last reply
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        • L leppie

          Without compiling the following code, what will be the result, if run?

          class Program
          {
          static void Main(string[] args)
          {
          object r = Foo(true);
          Console.WriteLine(r.GetType());
          Console.ReadLine();
          }

          static object Foo(bool e)
          {
          return e ? 0 : 0.0;
          }
          }

          Now compile and run the code? Are you surprised? If so, try figure it out, if not, then kudos to you :)

          xacc.ide - now with TabsToSpaces support
          IronScheme - 1.0 alpha 4a out now (29 May 2008)

          S Offline
          S Offline
          SomeGuyThatIsMe
          wrote on last edited by
          #19

          i say double, but one of our new devs, thought it was a bool, then an object, then gave up and had me explain it. person has the same title as me too, funny how i never cared about that stuff until i got one. hopefully the other new guy will do better.

          Please remember to rate helpful or unhelpful answers, it lets us and people reading the forums know if our answers are any good.

          1 Reply Last reply
          0
          • G Gary Wheeler

            Mustafa Ismail Mustafa wrote:

            double, and I'd be surprised if it were anything else...

            double, and I'd be surprised pissed off if it were anything else... (I'm in the process of learning C#)

            Software Zen: delete this;

            M Offline
            M Offline
            Mustafa Ismail Mustafa
            wrote on last edited by
            #20

            Gary Wheeler wrote:

            double, and I'd be surprised pissed off if it were anything else...

            I stand corrected :)

            Gary Wheeler wrote:

            (I'm in the process of learning C#)

            From what I remember, you're a C++er. Don't worry, you'll pick it up in no time flat, but you'll hate some stuff. const comes as a[n unpleasant] surprise and so do reflection issues. All in all, its a nice language :)

            Don't forget to vote if the response was helpful


            Sig history "dad" Ishmail-Samuel Mustafa "You're an idiot." John Simmons, THE Outlaw programmer "I realised that all of my best anecdotes started with "So there we were, pissed". Pete O'Hanlon Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

            G 1 Reply Last reply
            0
            • L leppie

              Without compiling the following code, what will be the result, if run?

              class Program
              {
              static void Main(string[] args)
              {
              object r = Foo(true);
              Console.WriteLine(r.GetType());
              Console.ReadLine();
              }

              static object Foo(bool e)
              {
              return e ? 0 : 0.0;
              }
              }

              Now compile and run the code? Are you surprised? If so, try figure it out, if not, then kudos to you :)

              xacc.ide - now with TabsToSpaces support
              IronScheme - 1.0 alpha 4a out now (29 May 2008)

              P Offline
              P Offline
              piyush7419820
              wrote on last edited by
              #21

              it will throw null exception.

              1 Reply Last reply
              0
              • M Mustafa Ismail Mustafa

                Gary Wheeler wrote:

                double, and I'd be surprised pissed off if it were anything else...

                I stand corrected :)

                Gary Wheeler wrote:

                (I'm in the process of learning C#)

                From what I remember, you're a C++er. Don't worry, you'll pick it up in no time flat, but you'll hate some stuff. const comes as a[n unpleasant] surprise and so do reflection issues. All in all, its a nice language :)

                Don't forget to vote if the response was helpful


                Sig history "dad" Ishmail-Samuel Mustafa "You're an idiot." John Simmons, THE Outlaw programmer "I realised that all of my best anecdotes started with "So there we were, pissed". Pete O'Hanlon Unix is a Four Letter Word, and Vi is a Two Letter Abbreviation

                G Offline
                G Offline
                Gary Wheeler
                wrote on last edited by
                #22

                Mustafa Ismail Mustafa wrote:

                From what I remember, you're a C++er.

                Yes indeed. My portion of our next product (the UI) will be written in C#, since we have a requirement to use some WPF controls supplied by another group. Now, I've got a couple thousand pages of books to read to get started :).

                Software Zen: delete this;

                1 Reply Last reply
                0
                • L leppie

                  Without compiling the following code, what will be the result, if run?

                  class Program
                  {
                  static void Main(string[] args)
                  {
                  object r = Foo(true);
                  Console.WriteLine(r.GetType());
                  Console.ReadLine();
                  }

                  static object Foo(bool e)
                  {
                  return e ? 0 : 0.0;
                  }
                  }

                  Now compile and run the code? Are you surprised? If so, try figure it out, if not, then kudos to you :)

                  xacc.ide - now with TabsToSpaces support
                  IronScheme - 1.0 alpha 4a out now (29 May 2008)

                  P Offline
                  P Offline
                  PIEBALDconsult
                  wrote on last edited by
                  #23

                  Yeah, makes sense to me, the ternary operator isn't allowed to return different types, so the int is implicitly cast to double, just as expected. Of course I had to add System. to the Console methods to get it to compile...

                  B C 2 Replies Last reply
                  0
                  • P PIEBALDconsult

                    Yeah, makes sense to me, the ternary operator isn't allowed to return different types, so the int is implicitly cast to double, just as expected. Of course I had to add System. to the Console methods to get it to compile...

                    B Offline
                    B Offline
                    BoneSoft
                    wrote on last edited by
                    #24

                    Personally, I'm always using my System. ;P


                    Visit BoneSoft.com for code generation tools (XML & XSD -> C#, VB, etc...) and some free developer tools as well.

                    1 Reply Last reply
                    0
                    • J Jorgen Sigvardsson

                      Smart? Nah, I give experience credit for this. Also, if you think about it, it has to be this way. Numbers aren't that different from objects in OOP. I think this code makes it more apparent: (boolval ? new Car() : new AirPlane()).Fly();Since C# is statically typed, method selection can't be left to runtime binding. :)

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                      Artiom Chilaru
                      wrote on last edited by
                      #25

                      In this case to be able to compile it you'll have to manually cast both objects to a base class, that has a Fly() methods :) While in the example of "? 0 : 0.0" the compiler does implicit casting

                      1 Reply Last reply
                      0
                      • L leppie

                        Without compiling the following code, what will be the result, if run?

                        class Program
                        {
                        static void Main(string[] args)
                        {
                        object r = Foo(true);
                        Console.WriteLine(r.GetType());
                        Console.ReadLine();
                        }

                        static object Foo(bool e)
                        {
                        return e ? 0 : 0.0;
                        }
                        }

                        Now compile and run the code? Are you surprised? If so, try figure it out, if not, then kudos to you :)

                        xacc.ide - now with TabsToSpaces support
                        IronScheme - 1.0 alpha 4a out now (29 May 2008)

                        C Offline
                        C Offline
                        cepi69
                        wrote on last edited by
                        #26

                        I would suggest you to read the "CLR via C#" book, by Jeffery Richter. ;P

                        1 Reply Last reply
                        0
                        • L leppie

                          Without compiling the following code, what will be the result, if run?

                          class Program
                          {
                          static void Main(string[] args)
                          {
                          object r = Foo(true);
                          Console.WriteLine(r.GetType());
                          Console.ReadLine();
                          }

                          static object Foo(bool e)
                          {
                          return e ? 0 : 0.0;
                          }
                          }

                          Now compile and run the code? Are you surprised? If so, try figure it out, if not, then kudos to you :)

                          xacc.ide - now with TabsToSpaces support
                          IronScheme - 1.0 alpha 4a out now (29 May 2008)

                          A Offline
                          A Offline
                          Alan Balkany
                          wrote on last edited by
                          #27

                          D'ohh! My answer was: "System.Int32". (At least I'm being honest!) Although I haven't tested it, in retrospect it makes sense that the two conditional values should be the same type. Good quiz leppie!

                          1 Reply Last reply
                          0
                          • P PIEBALDconsult

                            Yeah, makes sense to me, the ternary operator isn't allowed to return different types, so the int is implicitly cast to double, just as expected. Of course I had to add System. to the Console methods to get it to compile...

                            C Offline
                            C Offline
                            chaiguy1337
                            wrote on last edited by
                            #28

                            Yeah this has caught me a few times, usually with a compile-time error. Kind of annoying.

                            “Time and space can be a bitch.” –Gushie, Quantum Leap {o,o}.oO( Looking for a great RSS reader? Try FeedBeast! ) |)””’)            Built with home-grown CodeProject components! -”-”-

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                            0
                            • L leppie

                              Without compiling the following code, what will be the result, if run?

                              class Program
                              {
                              static void Main(string[] args)
                              {
                              object r = Foo(true);
                              Console.WriteLine(r.GetType());
                              Console.ReadLine();
                              }

                              static object Foo(bool e)
                              {
                              return e ? 0 : 0.0;
                              }
                              }

                              Now compile and run the code? Are you surprised? If so, try figure it out, if not, then kudos to you :)

                              xacc.ide - now with TabsToSpaces support
                              IronScheme - 1.0 alpha 4a out now (29 May 2008)

                              R Offline
                              R Offline
                              Roger Wright
                              wrote on last edited by
                              #29

                              leppie wrote:

                              compile and run the code

                              My computer leapt off the table, ran in circles, peed on the carpet, then spent the rest of the day sulking behind the couch, presumably calling Dial-a-Byte on my cellphone over and over again.

                              "A Journey of a Thousand Rest Stops Begins with a Single Movement"

                              1 Reply Last reply
                              0
                              • L leppie

                                Without compiling the following code, what will be the result, if run?

                                class Program
                                {
                                static void Main(string[] args)
                                {
                                object r = Foo(true);
                                Console.WriteLine(r.GetType());
                                Console.ReadLine();
                                }

                                static object Foo(bool e)
                                {
                                return e ? 0 : 0.0;
                                }
                                }

                                Now compile and run the code? Are you surprised? If so, try figure it out, if not, then kudos to you :)

                                xacc.ide - now with TabsToSpaces support
                                IronScheme - 1.0 alpha 4a out now (29 May 2008)

                                W Offline
                                W Offline
                                W i N D
                                wrote on last edited by
                                #30

                                The compiler's said test.cs(6,5): error CS0103: The name 'Console' does not exist in the current context test.cs(7,5): error CS0103: The name 'Console' does not exist in the current context because you aren't import System namespace or use full name like 'System.Console'

                                1 Reply Last reply
                                0
                                • L leppie

                                  Without compiling the following code, what will be the result, if run?

                                  class Program
                                  {
                                  static void Main(string[] args)
                                  {
                                  object r = Foo(true);
                                  Console.WriteLine(r.GetType());
                                  Console.ReadLine();
                                  }

                                  static object Foo(bool e)
                                  {
                                  return e ? 0 : 0.0;
                                  }
                                  }

                                  Now compile and run the code? Are you surprised? If so, try figure it out, if not, then kudos to you :)

                                  xacc.ide - now with TabsToSpaces support
                                  IronScheme - 1.0 alpha 4a out now (29 May 2008)

                                  U Offline
                                  U Offline
                                  User 4366736
                                  wrote on last edited by
                                  #31

                                  The Foo method is expecting a reference type (object), but it is getting a value type, probably double. Now the question is, does C# convert the value type to a reference type (boxing)? The reference type would be converted to a Nullable (double?), I don't think so. I don't think it will return a compile error. So I believe it will result in a runtime error (don't know what it would be). I'll run it after this post and see. Tony

                                  U 1 Reply Last reply
                                  0
                                  • U User 4366736

                                    The Foo method is expecting a reference type (object), but it is getting a value type, probably double. Now the question is, does C# convert the value type to a reference type (boxing)? The reference type would be converted to a Nullable (double?), I don't think so. I don't think it will return a compile error. So I believe it will result in a runtime error (don't know what it would be). I'll run it after this post and see. Tony

                                    U Offline
                                    U Offline
                                    User 4366736
                                    wrote on last edited by
                                    #32

                                    Interesting, the base type of the Double is a System.ValueType, and it's base type is System.Object. Yes, I am surprised. Thanks for the puzzle.

                                    1 Reply Last reply
                                    0
                                    • J Jorgen Sigvardsson

                                      Double I would imagine due to this: return e ? 0 : 0.0;. The thing with this if-expression, is that the true and false types must be of same or assignable types. In this case an int can be cast into a double, but not vice versa. Because of this, the compiler will promote the 0 to a 0.0, hence double.

                                      B Offline
                                      B Offline
                                      Blumen
                                      wrote on last edited by
                                      #33

                                      Hi, I ran this code and irrespective of what the parameter to foo() is, the output is system.Double

                                      Jörgen Sigvardsson wrote:

                                      The thing with this if-expression, is that the true and false types must be of same or assignable types. In this case an int can be cast into a double, but not vice versa. Because of this, the compiler will promote the 0 to a 0.0, hence double.

                                      I din't get this, could you explain this please? Regards, Blumen

                                      J 1 Reply Last reply
                                      0
                                      • B Blumen

                                        Hi, I ran this code and irrespective of what the parameter to foo() is, the output is system.Double

                                        Jörgen Sigvardsson wrote:

                                        The thing with this if-expression, is that the true and false types must be of same or assignable types. In this case an int can be cast into a double, but not vice versa. Because of this, the compiler will promote the 0 to a 0.0, hence double.

                                        I din't get this, could you explain this please? Regards, Blumen

                                        J Offline
                                        J Offline
                                        Jorgen Sigvardsson
                                        wrote on last edited by
                                        #34

                                        If we remodel the if-expression as a function, it could be written like this: T if-expr(bool, T trueExpression, T falseExpression). T is an implicit type generic parameter of sorts. The compiler will at compile time determine what it is. T will not be determined based on what is receiving it. When the compiler sees int var = boolExpr ? trueExpr : falseExpr, it will not try to deduce that T is an int. The compiler will however examine the types of trueExpression and falseExpression. In the original post, we had int and double. Because we said earlier that trueExpression and falseExpression must be of same type T, the compiler must choose between the two types without losing information. An int can "fit inside" a double, but a double can't fit inside an int. Thus the compiler selects T as being double. Since T was chosen to be double, the return type of the entire expression becomes T.

                                        -- Kein Mitleid Für Die Mehrheit

                                        B 1 Reply Last reply
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                                        • J Jorgen Sigvardsson

                                          If we remodel the if-expression as a function, it could be written like this: T if-expr(bool, T trueExpression, T falseExpression). T is an implicit type generic parameter of sorts. The compiler will at compile time determine what it is. T will not be determined based on what is receiving it. When the compiler sees int var = boolExpr ? trueExpr : falseExpr, it will not try to deduce that T is an int. The compiler will however examine the types of trueExpression and falseExpression. In the original post, we had int and double. Because we said earlier that trueExpression and falseExpression must be of same type T, the compiler must choose between the two types without losing information. An int can "fit inside" a double, but a double can't fit inside an int. Thus the compiler selects T as being double. Since T was chosen to be double, the return type of the entire expression becomes T.

                                          -- Kein Mitleid Für Die Mehrheit

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                                          B Offline
                                          Blumen
                                          wrote on last edited by
                                          #35

                                          Jörgen Sigvardsson wrote:

                                          If we remodel the if-expression as a function, it could be written like this: T if-expr(bool, T trueExpression, T falseExpression). T is an implicit type generic parameter of sorts. The compiler will at compile time determine what it is.

                                          I din't understand this because I'm not good with Generics yet. But I understood that if types to be compared are different, compiler makes a choice such that there is no loss of data, I hope I'm correct here. Vielen Dank :)

                                          J 1 Reply Last reply
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