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The canonical design of multithreaded applets is inherently flawed. You know what I’m talking about: the run method with the repaint/sleep statements embedded in a while(true). Any self-respecting operating systems
Instead of using #define macros to create a set of values, as in this (deprecated) example: #define JAN 1#define FEB 2//…#define DEC 12 Enum types are a significantly better choice:
Sometimes, an object must be converted into a built-in type (for instance, a string object passed as an argument to C function such as strcmp()) : //file Mystring.hclass Mystring {
When you instantiate an automatic object (e.g., on the stack) using its default constructor, mind that the correct syntax is: String str; //correct And not this: String str(); //entirely different
When designing a class hierarchy, you may face a decision between inheritance (aka IsA ) vs. containment (aka HasA) relation. For instance, if you are designing a Radio class, and
If a class may serve as a base class for others, its destructor should be virtual. This ensures RTTI support for objects of this class and objects derived from it,
When you have to “unconst” an object, as in this case: void print( unsigned char* c) { cout
When an array of object is instantiated, the default constructor (and only the default constructor) of each member is invoked automatically. If you define no constructors at all, the compiler
Struct instances created on the stack are uninitialized (i.e., contain garbage values). The easiest, most efficient, and future-proof way to initialize them is: struct PlainData {char [20] name;long ID;char [15]
In Swing 0.7, and probably later versions as well, the DefaultListModel class notifies its ListDataListeners every time a new element is added to the list model. For very large lists
C-style I/O is still supported in C++. However, the iostream objects offer 2 advantages over the printf() family: type safety and support for user-defined types. Consider the following example: void
Multi-dimensional arrays can be represented by arrays of arrays. For example, suppose that you want to create a 3×3 matrix, called Brady, and fill it with the strings shown in
The class java.io.PushbackInputStream in JDK 1.1.3 returns the wrong value from its available() method. If you look at the source code, it returns pos + super.available(); when it should really
This bug workaround identifies Windows operating systems and adds an identifier to the absolute root directory path to avert file problems. File root;String tmp;tmp = System.getProperty(“user.dir”);root = new File(tmp);while((tmp =
Using operator new (or malloc() in C) to create objects on the heap is expensive in terms of performance (allocating heap memory usually involves a long negotiation with the OS),
Objects created using new [] must be released using delete [] as in this example. It
When you need a constant integer member in an object, the easiest way to create one is by using a nameless enum, which can be used like any const int:
Passing large objects by value as function arguments is very inefficient. On the other hand, passing them by reference/address is dangerous since it enables the callee to change its arguments
Even experienced C++ programmers who have prior experience with C tend to use pointers excessively whereas references may be a better choice. Pointers may result in bugs like the following:
If you do not define a copy constructor and operator = , the compiler will create them automatically for you. However, there are cases when you have to define them
Using #define to create macro constants is not ideal. Macros are substituted by the preprocessor, so the compiler usually cannot detect anomalies such as type mismatch (see example); furthermore, most
One of the good things about destructors is that they are called automatically. There are rare cases, however, when you want to invoke an object
There are cases where you have to define several constructors (or constructors and operator = ) within one class, all of which perform some identical tasks (e.g., initialize members, allocate
Although Java’s String package is a lot more friendly than C’s string handling, you can still find yourself surprised by its behavior at times. Consider this code: import java.lang.String;public class
To present your applet in a visually pleasing way, it’s often handy to know the size of the screen that’s available for output. Fortunately, a built-in AWT function makes determining
Whenever you define a class member function which does not (and should not) change its object, it’s a good idea to define it as a const member function. There are
Did you ever feel the urge to use a nice Java class you just wrote as an ActiveX object on your Windows machine? Good news: you can do it in
Question: Can you explain to me how a linked list works with FILE I/O. For example, how do you add, modify, delete, and search for a student record in a
Question: I installed MS Visual C++ 5.0 at work and on my home machine. At work it’s fine running on Windows NT with 96 megs of RAM. On my home
Question: Can I have variable length fields in a structure. I have tried something like: typedef struct { int length; char data[length];}; but that won’t compile. Is there a way,