Many scientific/trigonometric/mathematical applications need the values of ‘pi’ and ‘e’ (the basis of natural logarithms) for calculations. The math class in the java.lang package has two static double constants that

Have you ever wanted to have 1:1 relation between tables (i.e. a table in which two columns act like primary key not combined but separately)?DB only supports a single column,

Declaring a virtual member function private may be useful when you wish to limit the number of derived classes that can override the given function. In such a case, you

Oftentimes, an application is packaged as a jar file. Ususally, you have to use a command line option to execute it. It would be easier to double click on the

If an application’s behavior is dependent on the amount of available memory, then this code fragment can be used to determine what action an application should take. For example, a

Sometimes, it is essential to know the fields and methods that are declared in a particular class. This is all the more important when there is no access to the

In ASP, Request object has five collections: QueryString, Form, Cookies, ClientCertificate, and ServerVariables. When you want to access information in one of these collections, you have the choice of writing

It’s very easy to create cross-tab queries in SQL. In the SELECT statement of a query, most databases allow you to use an expression with an aggregate function, not only

You can pack the XML Parser along with the Java Application you are shipping. The following steps show how to do this. I used the Apache’s Xerces and Xalan parsers

The following trick isn’t portable. Furthermore, even implementations that currently support it do not guarantee to support it in their future releases. Still, it can teach you a few things

Certain compiler and code analyzers can detect a missing enumerator in a switch statement. Consider: enum Seasons{ Winter, Spring, Summer, Fall};switch (s){case Winter: wearCoat(); break;case Spring: pruneGarden(); break;case Summer: goSwimming();

If you need to concatenate variables of different types to form a string, use a stringstream object. The header contains the declarations of the stringstream family of classes. Using its

There are two methods of reading a string from the standard input. The first one uses getline(), as in the following example: std::string name;getline(cin, name); // option #1 The second

The function std::set_new_handler() installs a function to be called when the global operator new or the global operator new[] fail. By default, operator new throws an exception of type std::bad_alloc

C++ defines three floating points datatypes: float, double and long double. Some existing implementations support only two (and in some cases only one) of these three. On such implementations, double

You can use a Shell Light Weight API to generate a relative path by using this code: Private Declare Function PathRelativePathToW _Lib “shlwapi.dll” (ByVal pszPath As Long, _ByVal pszFrom As

This function will determine whether or not a thread is running in the user context of the local Administrator account. You need to examine the access token associated with that

No native VB function returns a fractional part of a decimal number. However, by subtracting the whole portion, obtained with Fix, from the original value, you can derive the fractional

When you have to display a long file path in a limited amount of space, you can use a Shell Light Weight API to do the job for you.Create a

Control arrays are odd beasts in that they can have missing elements. The simplest way to iterate a control array uses this method: Dim i As IntegerFor i = Text1.LBound

In VB.NET, you can use the System.Array class to create an array with non-zero lower bounds. To do this, use the System.Array.CreateInstance method: Array.CreateInstance(Type, Lengths(), LowerBounds( ) ).If the array

In VB.NET, you can instantiate a new instance of an object inline, making your code more compact. This example shows both versions: Imports SystemPublic Class Author Private fName As String

Unlike VB6, VB.NET requires that you specify the default value of any Optional argument. In general you should use a value that is invalid under normal circumstances, so that the

The version of the Shell function included in VB.NET expands on the original version and supports an additional argument that enables you to specify whether to wait until the shelled

The Visual Studio debugger offers complete control on what happens when an application throws an exception, or calls a .NET method that throws an exception. You set all the relevant

Unlike VB6, in VB.NET the ParamArray keyword defines a true array object, which you can process using any of the methods of the Array class. For example, here’ s a

The Visual Basic .NET Err.Raise method and the Throw command are (partially) compatible. For example, you can use a Try…End Try block to catch an error raised with the Err.Raise