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Computer Programming
A category for questions about computer programming and programming languages.
10,506 Questions
What are low-level and high-level interfacing can you explain them?
The level determines the amount of abstraction between the source code and the target language. Assembly language is low-level because there is little to no abstraction between the source code and the machine code; it is a near 1:1 translation. All other languages are high-level, however the amount of abstraction varies. The more abstract, the easier a language is to use but the farther from the machine you get. Java is at the extreme end of the high-level languages, with very little low-level functionality. This is because Java compiles to byte code suitable for interpretation by the Java virtual machine. In other words you write code to suit a non-existent machine but one that is consistent across all platforms. C is at the opposite end, with the lowest level of abstraction of all the high-level languages. C++ is higher than C but is also a subset of C so it is ideally suited for mixing high and low level programming such that you will rarely need anything lower than C++.
How many programming language does Ada Lovelace developed?
None. Ada Lovelace is credited with creating the first algorithm intended to be carried out by a machine but she did not develop any programming languages. She died in 1852, a Century before machines were even capable of translating high-level code into machine code.
What is ORG in assembly language programming?
ORG is an assembler directive that sets the address of the next generated instruction or data byte.
What is sem post and sem wait functions?
The sem_wait() function locks the semaphore referenced by sem by performing a semaphore lock operation on that semaphore. If the semaphore value is currently zero, then the calling thread will not return from the call to sem_wait()until it either locks the semaphore or the call is interrupted by a signal.
Upon successful return, the state of the semaphore is locked and remains locked until the sem_post() function is executed and returns successfully. The sem_wait() function is interruptible by the delivery of a signal.
The sem_post() function unlocks the semaphore referenced by sem by performing a semaphore unlock operation on that semaphore.
If the semaphore value resulting from this operation is positive, then no threads were blocked waiting for the semaphore to become unlocked; the semaphore value is simply incremented.
If the value of the semaphore resulting from this operation is zero, then one of the threads blocked waiting for the semaphore will be allowed to return successfully from its call to sem_wait(). If the symbol _POSIX_PRIORITY_SCHEDULING is defined, the thread to be unblocked will be chosen in a manner appropriate to the scheduling policies and parameters in effect for the blocked threads. In the case of the schedulers SCHED_FIFO and SCHED_RR, the highest priority waiting thread will be unblocked, and if there is more than one highest priority thread blocked waiting for the semaphore, then the highest priority thread that has been waiting the longest will be unblocked. If the symbol _POSIX_PRIORITY_SCHEDULING is not defined, the choice of a thread to unblock is unspecified.
The sem_post() interface is reentrant with respect to signals and may be invoked from a signal-catching function.
What programming languages don't need an ide?
HTML, JAVASCRIPT, ASP, and PHP are good ones. There is also VbScript and jQuery. They are all coded in Notepad.
How computer with single CPU can run many programs?
Each running thread is allocated a time slice. When a thread's allocated time slice expires, the CPU state is saved and the next thread's state is restored. Thus each thread continues from exactly where it left off. The time slices themselves are just a few milliseconds in length. In this way many applications can appear to be running simultaneously. However, the more applications that are running, the slower they will execute because they each get fewer time slices per second. Applications are also prioritised so that high priority tasks get more CPU time than low priority tasks. Typically there are around 16 levels of priority, where 0 is the highest priority.
Can computer programmers create apps for smartphone like ios and droid devices?
Well yes. If you have a mac. if your on a Windows Computer there are ways to make the apps but you can't put them on your Ipod, Iphone, Ipad, ect
How viruses affecting the bluetooth?
it on atmosphere virues are effect by computer because it connect into atmosphere and so it some virues are arround in our atmosphere..
What does Binary code use to create a type of Morse code that the computer understands?
Binary code is the native language of the machine; no translation is necessary. However, the binary encoded data may be abstract, high-level instruction code (program source code) that must be compiled or interpreted in order to produce the required machine code the computer understands. A software program is used to perform this translation; each programming language provides its own compiler and/or interpreter specific to each machine type and operating system (the platform).
How do you use set and get in object-oriented programming?
A set function (or setter) is an object mutator. You use it to modify a property of an object such that the object's invariant is maintained. If the object has no invariant, a setter is not required.
A get function (or getter) is an object accessor. You use it to obtain a property from an object such that the object's invariant is maintained. If the object has no invariant, you do not need a getter.
Where would you use union in C language?
Subudhi Pamisetty
With a union, you're only supposed to use one of the elements, because they're all stored at the same spot. This makes it useful when you want to store something that could be one of several types. A struct, on the other hand, has a separate memory location for each of its elements and they all can be used at once.
union foo {
int a; // can't use both a and b at once
char b;
} foo;
struct bar {
int a; // can use both a and b simultaneously
char b;
} bar;
union foo x;
x.a = 3; // OK
x.b = 'c'; // NO! this affects the value of x.a!
struct bar y;
y.a = 3; // OK
y.b = 'c'; // OK
edit: If you're wondering what setting x.b to 'c' changes the value of x.a to, technically speaking it's undefined. On most modern machines a char is 1 byte and an int is 4 bytes, so giving x.b the value 'c' also gives the first byte of x.a that same value: union foo x;
x.a = 3;
x.b = 'c';
printf("%i, %i\n", x.a, x.b);
prints 99, 99
Why are the two values the same? Because the last 3 bytes of the int 3 are all zero, so it's also read as 99. If we put in a larger number for x.a, you'll see that this is not always the case: union foo x;
x.a = 387439;
x.b = 'c';
printf("%i, %i\n", x.a, x.b);
prints 387427, 99
To get a closer look at the actual memory values, let's set and print out the values in hex: union foo x;
x.a = 0xDEADBEEF;
x.b = 0x22;
printf("%x, %x\n", x.a, x.b);
prints deadbe22, 22
You can clearly see where the 0x22 overwrote the 0xEF.
BUT
In C, the order of bytes in an int are not defined. This program overwrote the 0xEF with 0x22 on my Mac, but there are other platforms where it would overwrite the 0xDE instead because the order of the bytes that make up the int were reversed. Therefore, when writing a program, you should never rely on the behavior of overwriting specific data in a union because it's not portable.
Which data structure has the fastest insertion procedure?
You are confusing data structures with data containers. Data containers include arrays, vectors, lists, and binary trees, to name but a few. The one thing they have in common is that they are all aggregates of homogeneous types. By contrast, a data structure is an aggregate of heterogeneous types.
As to which data container offers the fastest insertion, the reason we have so many container types in the first place is simply because there is no one container that gives optimal performance in all cases. If we need to insert at the back of a container, we will typically use a vector (a variable-length array). If we need to insert at both the back and the front of a container, we will typically use a list. If we need to maintain sorted order, we will typically use a binary tree.
However, these are merely guidelines. The only way to determine which container gives the best performance in any given application is to conduct your own performance tests. Remember also that containers are used for more than just insertion, so choosing a container based solely upon its insertion performance may not be the best option overall.
What is a high speed data searching and sorting in data structure algorithm?
Binary Search is the high speed data searching.Here in each recursion the is divided in two equal halves so that execution becomes easier.
Why is it important to have security on a webpage?
well security is most important for any web application or websites, if your website is not secure then anyone can post or edit your contents. that may violate any rules or norms, can cause serious problem to you.
Is an API the same thing as an XML feed?
API: Application Programming Interface, or Available Public Interface
It is a general term to what is available for one software unit to interact with another one. Usually APIs are method signatures (contracts).
XML feed is just an XML (in a file or a textual data type such as a string). It may not have anything to do with API, or in some ways to describe an API. It may be a part of the API signature (as the returned type or as the argument to API). It may describe the API in XML format. But XML feed itself should not consider an API.
What is process control block PCB?
- The OS must know specific information about processes in order to manage, control them and also to implement the process model, the OS maintains a table (an array of structures)
, called the process table
, with one entry per process
.
- These entries are called process control blocks
(PCB) - also called a task control block.
- This entry contains information about the process'state, its program counter, stack pointer, memory allocation, the status of its open files, its accounting and scheduling information, and everything else about
the process
that must be saved when the process is switched from running to ready or blocked state so that it can be restarted later as if it had never been stopped
What phrase is placed in the starting terminal symbol of a module in a flowchart?
the name of the module
Why Smalltalk is a pure object oriented language?
Smalltalk is a "pure" object-oriented programming language, meaning that, unlike Java and C++, there is no difference between values which are objects and values which are primitive types. In Smalltalk, primitive values such as integers, booleans and characters are also objects, in the sense that they are instances of corresponding classes, and operations on them are invoked by sending messages. A programmer can change the classes that implement primitive values, so that new behavior can be defined for their instances-for example, to implement new control structures-or even so that their existing behavior will be changed. This fact is summarized in the commonly heard phrase "In Smalltalk everything is an object", which may be more accurately expressed as "all values are objects", as variables are not.
Since all values are objects, classes themselves are also objects. Each class is an instance of the metaclass of that class. Metaclasses in turn are also objects, and are all instances of a class called Metaclass. Code blocks are also objects.
| --- add (enqueue) ---> ... | --- remove (dequeue) ---> |
By definition, First-in-First-out is the primary characteristic of being a queue. For any given time, the position of adding an item, or enqueue, is always from the left (directions shown as above, but they are just abstraction), and deleting one, or dequeue, is always from the right. The derived property or attribute of a queue is the adding position is always >= deleting position
When the positions of these 2 fundamental operations are at the same position, the queue is EMPTY. And we know there is no way to be less than EMPTY of a queue, right?! Thus, insertion and deletion positions of the queue are NEVER interchanged.
If they could be interchanged, then the thing you have is just a container, not a specialized container to fulfill First-IN-First-OUT (QUEUE). (the ones in the container are not served as the order they came in)
How do you download 2 files from j downloader with out waiting 40 minutes?
Just reset your internet modern by closing and re opening it
How do you read the number of capital letters in a input file using c language?
#include <stdio.h>
#include <ctype.h>
...
int caps = 0;
int c;
file = fopen ("InputFile", "r");
while ((c = fgetc (file)) != EOF) {
if (isupper (c)) ++caps;
}
fclose(file);
...
