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Spreading Data across Months on a Single Row

This is a SQL trick for spreading out data across months on a single row. It also works with Sybase TSQL. The 1-ABS(SIGN()) function will evaluate to zero for all

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C++ Smart Pointers

C++ smart pointers are the idea of using a selector to access a class. This gives the class writer an option to control access to class members and function. For

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Automate Microsoft Office Programs from within ASP

Creating dynamic Microsoft documents may be useful. The problem is that creating Word documents in ASP will result in an error saying that IIS cannot run out of process components.

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Get Value from the Control Irrespective of Control Type

This code shows how to get value from the control irrespective of the control type used in the client side Javascript. function GetValue(ControlName,FormName){var Control=document.forms[FormName].elements[ControlName]alert(Control.type) switch(Control.type) { case “select-one”: case “select-multiple”:

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Using Count(*)

Using Count(*) is generally better than using Count() with a specific column name, because it gives the query engine the flexibility to find out the row count any way it

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How to Make a Private Member Public

You can make a privately inherited member public by specifying its access modifier in the derived class. For example: #include class base{ public: int a; int b; base() { a=10;

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Executing a Java Application in an End User System

The Java 2 Runtime Environment is the minimum standard Java computing environment for running applications written in the Java programming language. It contains the Java virtual machine, Java core classes,

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Using the Java Robot Class

This tip demonstrates a user interaction (mouse move & mouse click) using native Robot methods.Here’s the algorithm of the program:1. Quickly to move the mouse cursor to the upper left

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Use Mouse Wheel to Control JSpinner

Merlin (JDK1.4) introduces two new features: JSpinner and MouseWheelListener. Sometimes it is convenient to control the spinner values with the mouse wheel. Here’s an example: import javax.swing.*;import java.awt.event.*;public class TestSpinner

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Create a Thread to Execute Short Code

Sometimes you want to create a thread to run something trivial, like when you’re debugging your code. This is a quick way to do it: new Thread(new Runnable() { public

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CPU Monitor

This application shows the percentage of the used CPU for any Windows system with up to 32 processors. The code that deals with the API to request the CPU information

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Incremental searches within list boxes

The DBList and DBCombo controls expose a MatchEntry property, that – when set to True – permits to perform quick incremental searches by simply typing the searched sequence of characters.

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Extended user interface for combo boxes

Apart from the different kind of combo boxes you can obtain by manipulating the Style property, another feature is made available by Windows when dealing with combo box controls, the

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Using Enter to move to next field

Most MsDos programs used the Enter key to move from one field to the next one. You can easily simulate this behavior by setting the form’s KeyPreview property to True

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Mutually exclusive list boxes

Many Windows programs use two adjacent list box controls to let the user select a number of items from a list of available values; such list boxes are mutually exclusive,

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Move focus with Up and Down keys

In all standard controls, Up and Down arrow keys move the focus on the previous or next control in the TabIndex order, respectively. This contrasts with text boxes, where these

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SetFileSize – Trim or extend a file’s size

Option ExplicitPrivate Declare Function CreateFile Lib “kernel32” Alias “CreateFileA” (ByVal _ lpFileName As String, ByVal dwDesiredAccess As Long, _ ByVal dwShareMode As Long, lpSecurityAttributes As Any, _ ByVal dwCreationDisposition As

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Avoid Unused Command Line Arguments

Many code wizards and automated source code generators synthesize the following main() template, even if the application doesn’t use command line arguments: int main(int argc, char* argv[]){ return 0;} This

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Constructor Call Sequence

The constructors in a class hierarchy execute in the following sequence: base class constructors are called first, then member object’s constructors, and finally, the constructor of the derived class executes.

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Disabling Further Derivation of a Class

Although the advantages of disabling further derivation of a class are often doubtable, C++ allows you to do that by declaring a class’s constructor and other special member functions private.

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The auto Keyword

‘auto’ is undoubtedly the least used C++ keyword. This is because it’s always redundant. auto indicates local automatic storage type, for example: int main(){ auto int x; auto char s[10];}

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Detecting the vptr’s Location

The precise location of the vptr (the pointer to the class’s table of virtual functions’ addresses) is implementation-dependent. Some compilers, e.g., Visual C++ and C++ Builder, place it offset 0,

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Virtual Base Classes Must Have a Default Constructor

Virtual inheritance imposes several restrictions. One of them is that you cannot use a class that has no default constructor as a virtual base class. Consider the following program: struct

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Dividing a JList

Normally, a list of items in a Java application is presented in a JList or JComboBox. If all of the listed items are created equally, the list handles them quite

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Auto Start an Application from the Registry

Here is an example of how to make your application auto start from the registry.The code also shows how to query and clear this. ‘Module: Module1 Option Explicit Private Const