rokoder

Tag: best pratices

  • C++ Templates, not so generic

    Lets start with basic ideology of .h and .cpp files. When building libraries, the idea is to share only your header files and not your implementation (mean .cpp files). This is also the basics OOP’s encapsulation, abstraction etc, to hide the implementation details.

    Now templates in C++ violates this encapsulation principle, bcoz C++ is a compiled language. And compiler generates all the needed (generic) code during compilation (it is different from Java as in Java this code can be generated in Java Run Time during execution and not at compilation. As Java compiled .class files contains enough info to generate a specific implementation later). Now to adhere to OOP we end up with fragile templates which are not 100% generic in nature.

    Now there are two ways to implement templates.
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  • Android missing MENU button

    Well since ICS, h/w MENU button is having a life of uncertainty on a phone. It may or may not be present. I learnt that the hard way, so thought of sharing this with everyone who is in the same boat. And some times (which sometimes becomes often) Android sdk docs are not very thorough (but yeah they are on the right track and doing better now). Here we ll consider two scenarios:

    Scenario 1: App does not use standard title bar but have menu options
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  • Hello World! to Path on Windows

    Well working with open source projects on Windows can be painful sometimes. I had faced this issue when I was working Tomcat, JBoss etc. on Windows.

    The issue we are talking about is `space` in file names. Lest take one example, JBoss like apps won’t work fine if your Java is installed in `Program Files`. Which generally is the case as the setup you get from Oracle installs it there. People use quick hack to copy the Java folder from there to root dirs, so that there is no `space` in the file path.

    Well there is another way to get the short name for a path in Windows. This is neat owes its roots to old 8 char long file names on old machines. Sometimes old legacy saves you in the new world….:)

    dir /X

    D:\>dir /X
 Volume in drive D is PROG_FILES
 Volume Serial Number is XXXX-XXXX

 Directory of D:\

03/11/2010  09:23 PM    <DIR>                       audio
09/29/2011  10:15 PM    <DIR>          GAMEFI~1     Game Files
03/11/2010  09:30 PM    <DIR>          INTELG~1     intelgraphics
12/17/2011  03:18 PM    <DIR>          PROGRA~1     Program Files
05/20/2011  07:08 PM    <DIR>                       tmp
               0 File(s)              0 bytes
               5 Dir(s)  29,142,163,456 bytes free

D:\>

    You can see that `Program Files` have a short name displayed next to it. Now we can use the short name in our environment variables/settings and have our Java installed in `Program Files`. This gives us a benefit as we are going to upgrade Java we don’t have to move it again to the root folder as we would have done if used the traditional approach to get rid of `space`.

  • Faster way to extract file name

    Working with unix shell and no way you wont end up extracting file names from paths. Well there is a usual way to do it.

    >basename /my/big/long/path/to/a/little/bitty/file
file

    Here is another way:

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  • Java to C++

    Many times people from Java endup writing C++ code and vice versa (for vice versa check notes below). This is the beauty of working in such a dynamic/vast programming eco-system. This blog is to help them create an analogy between the two.

    Below we have a sample Java code which we like to convert to C++.

    interface MyInterface {
  void func1();
  int func2(int x, int y);
}

interface MyAnotherInterface {
  void func3();
  int func4(int x, int y);
}

abstract class MyAbstract implements MyInterface {
  void func1() {
    System.out.print("In func1");
  }
}

class MyConcreteClass extends MyAbstract
  implements MyAnotherInterface {
  int func2(int x, int y) {
    System.out.print("func2 x=" + x + ",y=" + y);
  }

  void func3() {
    System.out.print("in func3");
  }

  int func4(int x, int y) {
    System.out.print("func4  x=" + x + ",y=" + y);
  }
}

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