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Articles on Trending Technologies
Technical articles with clear explanations and examples
What is the importance of a SwingWorker class in Java?
A SwingWorker class enables us to perform an asynchronous task in a worker thread (such as a long-running task) then update Swing components from the Event Dispatch Thread (EDT) based on the task results. It was introduced in Java 1.6 Version.SwingWorker classThe java.swing.SwingWorker class is a task worker, which performs time-consuming tasks in the background.A SwingWorker instance interacts with 3 threads, Current thread, the Worker thread, and the Event Dispatch thread(EDT).The Current thread calls the execute() method to kick off the task to the background and returns immediately.The Worker thread executes our own version of the doInBackground() method continuously in the background.The Event Dispatch Thread (EDT) wakes up from time to ...
Read MoreWhat is the default type of a hexadecimal value in MySQL?
As we know that in numeric contexts the hexadecimal values act like integers and in string contexts they act like binary string. It can be understood with the help of the following example,mysql> Select X'5455544F5249414C53504F494E54'; +---------------------------------+ | X'5455544F5249414C53504F494E54' | +---------------------------------+ | TUTORIALSPOINT | +---------------------------------+ 1 row in set (0.07 sec)But, if we are talking about default type of hexadecimal value in MySQL, then it is a string.
Read MoreHow can I profile C++ code running in Linux?
There are many great profiling tools for profiling C++ programs on Linux. The most widely used tool is Valgrind. It is a programming tool for memory debugging, memory leak detection, and profiling. You can use valgrind by passing the binary to it and setting the tool to callgrind. First generate the binary by compiling the program −$ g++ -o hello.cpp hello Now use valgrind to profile it: $ valgrind --tool=callgrind ./helloThis will generate a file called callgrind.out.x. You can read this file using a tool called kcachegrind.If you're using gcc, you can use the inbuilt profiling tool, gprof. You can ...
Read MoreThe most elegant way to iterate the words of a C/C++ string
There is no one elegant way to iterate the words of a C/C++ string. The most readable way could be termed as the most elegant for some while the most performant for others. I've listed 2 methods that you can use to achieve this. First way is using a stringstream to read words seperated by spaces. This is a little limited but does the task fairly well if you provide the proper checks. example#include #include #include using namespace std; int main() { string str("Hello from the dark side"); string tmp; ...
Read MoreWhat are the rules about using an underscore in a C++ identifier?
From MSDN docs −Use of two sequential underscore characters ( __ ) at the beginning of an identifier, or a single leading underscore followed by a capital letter, is reserved for C++ implementations in all scopes. You should avoid using one leading underscore followed by a lowercase letter for names with file scope because of possible conflicts with current or future reserved identifiers.So you should avoid using names like −__foo, __FOO, _FOOAnd names like the following should not be used in the global namespace −_foo, _barOther than this, there are some more prefixes like LC_, SIG_, and suffixes like _t ...
Read MoreCan a local variable's memory be accessed outside its scope in C/C++?
Let us look at an example where you MIGHT be able to access a local variable's memory outside its scope.Example#include int* foo() { int x = 3; return &x; } int main() { int* address = foo(); cout
Read MoreWhy can C++ templates only be implemented in the header file?
When you instantiate a template in C++, the compiler creates a new class. This class has all the places where you placed the template arguments replaced with the actual argument you pass to it when using it. For example −template class MyClass { T foo; T myMethod(T arg1, T arg2) { // Impl } };And somewhere in your program use this class, MyClass x;The compiler creates a new class upon encountering this for every type argument you pass it. For example, if you created 3 objects with different template arguments you'll get 3 classes, ...
Read MoreWhile running MySQL statements in batch mode, how can we print, along with output, which statements are getting executed?
By using –v option in batch mode, the MySQL statements can be printed along with output. For example, after running the same query in batch mode with –v option we will get the statement printed along with output.C:\Program Files\MySQL\bin>mysql -u root -p gaurav < hh.sql -v Enter password: ***** -------------- select * from hh -------------- id 1 2It is showing the statement select * from hh which is written in the file hh.sql.
Read MoreWhat are literals in C++?
A literal is any notation for representing a value within the source code. They just exist in your source code and do not have any reference a value in memory. Contrast this with identifiers, which refer to a value in memory.There are several types of literals in C++. Some of the examples of literals are −"Hello" (a string)3.141 (a float/double)true (a boolean)3 (an integer)'c' (a character)Things that are not literals −bar = 0; (a statement)3*5-4 (an expression)std::cin (an identifier)
Read MoreWhat is different between constant and variable in C++?
Variable and constant are two commonly used mathematical concepts. Simply put, a variable is a value that is changing or that have the ability to change. A constant is a value which remains unchanged.For example, if you have a program that has a list of 10 radii and you want to calculate the area for all of these circles. To find the area of these circles, you'll write a program that will have a variable that will store the value of PI and this value will not change throughout the program. Such values can be declared as a constant.In the ...
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