The GNS News!

OOP and C#: Making a Sample Class

January 02 2009 03:14:19 EST

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HTML + CSS = A Calendar? Cool!

December 20 2008 23:39:14 EST

For this sample, I used a PHP function, getdate, to have the PHP engine build me an array of the day, month, year, etc. of whenever the page is served. If you are loading a previous entry, say, from a database, you will want to pass a time-stamp into the function. I found this format gave me the best results: Month 00 0000 HH:MM:SS calendar.php

Download Get the source code for this tutorial here: calendar.zip]]>[...]

Something Wicked, This Way Comes...

December 18 2008 12:05:00 EST

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Opining About My Future

December 08 2008 14:38:00 EST

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Commercial Software Recommendations

November 30 2008 21:44:00 EST

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My Favorite Free Security Software

November 25 2008 13:34:00 EST

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Java Classes

November 21 2008 16:08:00 EST

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Visual Basic

November 21 2008 16:02:00 EST

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An Interesting Use of a C# Foreach Loop

November 04 2008 14:12:00 EST

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Coding Like Forrest Gump

October 24 2008 16:09:00 EST

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Pretty URLs For Everyone!

October 13 2008 01:00:00 EST

[...]

Why Sherlock Holmes Would Have Made A Kick-Ass Programmer

October 08 2008 20:59:00 EST

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Java: Multiplatform Powerhouse

October 08 2008 18:46:00 EST

Less than < Greater than or equal to >= Less than or equal to <= Boolean logical operators AND & OR | XOR ^ OrElse || AndAlso && NOT ! AND assignment &= OR assignment |= XOR assignment ^= Equal to == Not equal to != Ternary if-then-else ?: Constant variables Use keyword final. Must be initialized when declared. Convention dictates that constants be identified by using UPPERCASE notation: final type VARIABLE-NAME = value; Inheritance Use keyword extends to derive from a parent (base) class. Use keyword super to access the parent (base) class from a derived (child) class. Abstract defines a class or method that cannot be instantiated. Final defines a class that cannot be derived (inherited) from. Use the keyword package to define a namespace. Use the keyword import to include an external package (project) into the current project. Standard Library Contained within the java package. Interfaces Can be thought of as an action plan for your classes; that is, it defines WHAT your class must do, but not HOW it does it. Any class that uses the interface must implement all aspects of the interface. Exception: an abstract class can implement only part of the interface. Any child classes must then implement the remainder of the interface. Interface methods/functions must be public. Interfaces cannot have instance variables. Interfaces can have variables, but they are implicitly static and final. Interfaces can derive from other interfaces, using the extends keyword. Use keyword implements to add an interface to a class object. Want a copy of my notes? If for some odd reason you find this useful, you can download a .doc version here.]]>[...]

C# : Creating a Custom Class

October 03 2008 13:29:00 EST

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C# : .NET's Native Tongue

October 03 2008 11:13:00 EST

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C/C++ : Creating a Custom Class

October 03 2008 12:57:00 EST

instead. The Constructor When you create an instance of your class, the constructor is used to set your member variables (variables local to this class) to a known state, or value. In other words, it initializes those variables. This clears out any data that may have previously existed in the location in memory in which our new variables now reside. We do this to make certain that our program will not be crashed by random invalid data. The Deconstructor This basically a self-destruct button for our class object. When the object goes out of scope, it's deconstructor is called to destroy the object. This frees up any resources the object may have been using (usually memory). Class-level Functions Class functions are normally used in one of two ways: To provide access to our (preferably) private member variables. To implement class-level logic, such as calculations, that do not need to be (and perhaps shouldn't be) exposed to the user of our class. Function Examples Let us suppose our class, SampleClass, has a couple of member variables declared: char name[25] and int age. Now, if we want to be good OOP programmers (and we do!), we need to enforce encapsulation. That means we should make these variables private, since we don't want any ol' bit of code to be able to modify these variables unless we say it can. So we have this: • SampleClass.h #pragma once class SampleClass { public: � SampleClass( void ); // constructor � ~SampleClass( void ); // deconstructor � private: � // internal variables and functions go here char name[25]; � int age; � public: � /* shared variables and external functions � go here */ }; Since our variables are now private, we need a way of accessing and/or modifying them. Suppose for now we just want to be able to view the values of our object's variables. We can create a function for each variable that will do just that, like so: • SampleClass.h #pragma once class SampleClass { � public: � SampleClass( void ); // constructor � ~SampleClass( void ); // deconstructor � private: � // internal variables and functions go here � char name[25]; � int age; � public: � /* shared variables and external functions � go here */ � char* GetName( void ); � int GetAge( void ); }; • SampleClass.cpp #include "SampleClass.h" // default constructor SampleClass::SampleClass( void ) { � /* place code here that needs to execute � when an instance of our class is created */ } // deconstructor - this is called when our class object is no longer being used. SampleClass::~SampleClass( void ) { } char* SampleClass::GetName( void ) { /* place code here that needs to execute � when this function is called */ � return name; } int SampleClass::GetAge( void ) { � /* place code here that needs to execute � when this function is called */ � return age; } The return type of the function needs to match the data type of the variable whose value we want to return as a result of calling this function.]]>[...]

C/C++ : Includes

October 03 2008 10:55:00 EST

or #include . The only difference is that the former tells the compiler to look within the STL (Standard Template Library) for the source code, while the latter instructs the compiler to look in the local project folder. Certain header files seem to see a lot of use in low-level programming courses, especially those that focus on creating console-based programs. These include, but are not limited to: iostream iomanip list map stdlib string math As you read on, I will try to explain the use of each class, and show ways to implement it in your code. iostream From the MSDN Standard C++ Library Reference: [This class] declares objects that control reading from and writing to the standard streams. This is often the only header you need to include to perform input and output from a C++ program. Specifically, iostream contains the following functions: cerr, cin, clog, cout, wcerr, wcin, wclog, and wcout. The functions used most often are cin and cout. These are used for console input and output, respectively; in other words, to read in character input from a console window and display character output back out to the console window. iomanip This class is used to manipulate the input and output sent and received by the console window. Iomanip contains the following functions: resetiosflags, setbase, setfill, setiosflags, setprecision and setw. The functions I used most often are setfill, setprecision and setw. These are used for formatting the output sent to the console window. setfill is used to define an automatically-inserted character, setprecision is used to set the number of trailing digits displayed, and setw sets a minimum width to an output string. Using these three functions together, it is quite easy to format your output to mimic, say, an ATM screen, with the output formatted correctly for currency, without need for excessive code. list The easiest way to define the list class is to think of it as an automatic array. A list object is a dynamically re-sized collection of other objects, such as integers, floats, characters, and pointers. map The map class is very similar to the list class, with the exception being that a map object's collection is automatically sorted. stdlib This class is mostly used to implement legacy C code. It contains a long list of functions. The functions I have used most often are: atof, atoi, atol, rand, and srand . The first three, atof, atoi and atol, are used to convert a character string into, in order, a float, integer, or long integer value. rand is used to generate a pseudo-random number. srand is used to seed, or initialize, the random number generator, which helps to increase the randomness of any subsequent calls to the rand function. string The string class is easily the most welcomed class to be added the STL, as it saves programmers from having to manually build either their own string class for each program or from having to deal with the complexities of character arrays. The string class implements it's own overloaded operators, and gives us access to the function getline, which is extremely useful for when you wish to read in a line of text (from the console window) that contains spaces, a condition that the character inputs have issues dealing with. math The math class, according to cplusplus.com, declares a set of functions to compute common mathematical operations and transformations. These include: acos, asin, atan, atan2, ceil, cos, cosh, exp,fabs, floor, fmod, frexp, ldexp, log, log10, modf, pow, sin, sinh, sqrt, tan, and tanh.]]>[...]

C/C++ : Power at Your Fingertips

October 03 2008 10:36:00 EST

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MySQL: OpenSource Data Storage

October 02 2008 17:59:00 EST

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JavaScript

October 02 2008 17:14:00 EST

Page Title Goes Here • samplepage.html. JavaScript embedded in document. Page Title Goes Here As you can see, there is a

The GNS News!

OOP and C#: Making a Sample Class

HTML + CSS = A Calendar? Cool!

Something Wicked, This Way Comes...

Opining About My Future

Commercial Software Recommendations

My Favorite Free Security Software

Java Classes

Visual Basic

An Interesting Use of a C# Foreach Loop

Recommended Reading

Coding Like Forrest Gump

Pretty URLs For Everyone!

Why Sherlock Holmes Would Have Made A Kick-Ass Programmer

Java: Multiplatform Powerhouse

C# : Creating a Custom Class

C# : .NET's Native Tongue

C/C++ : Creating a Custom Class

C/C++ : Includes

C/C++ : Power at Your Fingertips

MySQL: OpenSource Data Storage

JavaScript