You have not selected any file s to download. A download manager is recommended for downloading multiple files.
WPbytes in sizeas compiled in the small model with Borland and Microsoft compilers with optimization on opt and off no opt. ASM ; Assembler subroutine to perform a bit checksum on the file ; opened on the passed-in handle.
Stores the result in the ; passed-in checksum variable. Returns 1 for success, 0 for error. Optimization makes code faster, but without proper design, optimization just creates fast slow code. Well, then, how are we going to improve our design?
Know the Territory Just why is Listing 1. The C library implements the read function by calling DOS to read the desired number of bytes. I figured this out by watching the code execute with a debugger, but you can buy library source code from both Microsoft and Borland.
That means that Listing 1. For starters, DOS functions are invoked with interrupts, and interrupts are among the slowest instructions of the x86 family CPUs. Then, DOS has to set up internally and branch to the desired function, expending more cycles in the process.
Finally, DOS has to search its own buffers to see if the desired byte has already been read, read it from the disk if not, store the byte in the specified location, and return. All of that takes a long time—far, far longer than the rest of the main loop in Listing 1.
In short, Listing 1. You can verify this for yourself by watching the code with a debugger or using a code profiler, but take my word for it: How can we speed up Listing 1. It should be clear that we must somehow avoid invoking DOS for every byte in the file, and that means reading more than one byte at a time, then buffering the data and parceling it out for examination one byte at a time.
The results confirm our theories splendidly, and validate our new design.
As shown in Table 1. To the casual observer, read and getc would seem slightly different but pretty much interchangeable, and yet in this application the performance difference between the two is about the same as that between a 4.
Make sure you understand what really goes on when you insert a seemingly-innocuous function call into the time-critical portions of your code. In other words, know the territory! Spend your time improving the performance of the code inside heavily-used loops and in the portions of your programs that directly affect response time.
Let C do what it does well, and use assembly only when it makes a perceptible difference. Always Consider the Alternatives Listing 1. Like readgetc calls DOS to read from the file; the speed improvement of Listing 1. Easier, yes, but not faster. Every invocation of getc involves pushing a parameter, executing a call to the C library function, getting the parameter in the C library codelooking up information about the desired stream, unbuffering the next byte from the stream, and returning to the calling code.
That takes a considerable amount of time, especially by contrast with simply maintaining a pointer to a buffer and whizzing through the data in the buffer inside a single loop.
There are four reasons that many programmers would give for not trying to improve on Listing 1. The code is already fast enough.
The C library conveniently handles the buffering of file data, and it would be a nuisance to have to implement that capability. The second reason is the hallmark of the mediocre programmer. Know when optimization matters—and then optimize when it does!
The third reason is often fallacious. C library functions are not always written in assembly, nor are they always particularly well-optimized.The protected access specifier hides its member variables and functions from other classes and objects.
This type of variable or function can only be accessed in child class. It becomes very important while implementing inheritance. Cay S. Horstmann and Gary Cornell explain inheritance, which allows you to create new classes that are built on existing classes. When you inherit from an existing class, you reuse (or inherit) its methods and fields and you add new methods and fields to adapt your new class to new situations.
Gimpel Software's PC-lint and FlexeLint On-Line Demos. On-Line Message Reference for FlexeLint and PC-lint (aka FlexeLint for Windows). Like any programming language, the Java language has its own structure, syntax rules, and programming paradigm.
The Java language's programming paradigm is based on the concept of OOP, which the language's features support. Explanation: (This note was last updated in August ) WONTFIX.
9: This is a note to the text, rather than an erratum. The small-font note at the bottom of the page states "At the time of writing, the stable Linux kernel is still supported ". Access specifiers defines the access rights for the statements or functions that follows it until another access specifier or till the end of a class.
The three types of access specifiers are "private", "public", "protected".