Programming Articles - Page 2727 of 3363

In C++, fabs is used to calculate the absolute value of a floating-point number. It is a function and defined to a header file. The fab() FunctionThis fabs() function accepts one argument, which is a floating-point number (double, float, or long double), and returns its absolute value as a floating-point number of the same type. Syntax Following is the syntax to fabs() function: double fabs(double x); The fabs() function is mostly used when we need to find the non-negative magnitude of a number. Using fabs() with positive and negative values Here, we will demonstrate how fabs() handles ... Read More

Every program runs as a process in Linux operating system. When a process ends or gets disconnected from its parent, special types of processes can be created. These processes are known as zombie and orphan processes. Details about the zombie and orphan processes are given as follows: Zombie Processes A zombie process is a process whose execution is completed but it still has an entry in the process table. Zombie processes usually occur for child processes, as the parent process still needs to read its child's exit status. Once this is done using the wait system call, the zombie process ... Read More

The Copy and Swap Idiom in C++ is a technique used in assignment operations. This consists of two steps: Discarding an object's old state and building a new state for it. The destructor is used for the first step and a copy constructor does the second step. Implementing both of these is straightforward. But when overloading the assignment operator, it can become quite difficult to implement. The copy and swap idiom is a solution for the same. This idiom uses the copy-constructor to build a local copy of the data. It then swaps the old data with the new data ... Read More

Type inference (or, type deduction) refers to the automatic detection of the data type of an expression in a programming language. In C++, the auto keyword is used for automatic type deduction.For example, you want to create an iterator to iterate over a vector, you can simply use auto for that purpose.It is helpful, when dealing with complicated STL containers, iterators, and lambda functions where it may be hard to write the full type. This can be achieved using auto, decltype, and decltype(auto) keywords. These approaches help in letting the compiler understand the correct data types without explicitly declaring them. ... Read More

In C++, the strand sort is a recursive sorting algorithm. It is used to extract increasing subsequences repeatedly (called strands) from the input list and merge them into a sorted list. There are multiple libraries that can be used for different purposes. This sorting is one of them. This sorting technique is particularly good for sorting linked lists, but can be used with arrays too. The following is a list of approaches for strand sorting in C++: These approaches is to extract sorted strands (in increasing/descending order) from the unsorted list and merge them one by one into a final ... Read More

In this section we will see how to perform sorting algorithm in C++. A sorted array is an array in which each of the elements are sorted in some order such as numerical, alphabetical etc. There are many algorithms to sort a numerical array such as bubble sort, insertion sort, selection sort, merge sort, quick sort, heap sort etc. More details about sorting the array using selection sort are given below.The selection sort is a sorting method that yields a sorted array. It does so by repeatedly finding the smallest element in the array and interchanging it with the element ... Read More

Yes, the namespace can be nested in C++. We can define one namespace inside another namespace. This makes it easier for developers to design a more structured and hierarchical format for their code. Syntax The following is the syntax as below : namespace namespace_name1 { // code declarations namespace namespace_name2 { // code declarations } } You can access members of a nested namespace by using resolution operators as follows: // to access members of namespace_name2 ... Read More

You can add/set an auto increment constraint to a column in a table using the ALTER TABLE command.SyntaxALTER TABLE table_name ADD id INT PRIMARY KEY AUTO_INCREMENTAssume we have a table named Dispatches in the database with 7 columns namely id, CustomerName, DispatchDate, DeliveryTime, Price and, Location with description as shown below:+--------------+--------------+------+-----+---------+-------+ | Field        | Type         | Null | Key | Default | Extra | +--------------+--------------+------+-----+---------+-------+ | ProductName  | varchar(255) | YES  | UNI | NULL    | | | CustomerName | varchar(255) | YES  |     ... Read More

Consider a situation, when we have two persons with the same name, Zara, in the same class. Whenever we need to differentiate them definitely we would have to use some additional information along with their name, like either the area, if they live in different area or their mother’s or father’s name, etc.Same situation can arise in your C++ applications. For example, you might be writing some code that has a function called xyz() and there is another library available which is also having same function xyz(). Now the compiler has no way of knowing which version of xyz() function ... Read More

You can drop a constraint on a column of a table using the ALTER TABLE command.SyntaxALTER TABLE table_name DROP CONSTRAINT MyUniqueConstraint;Assume we have a table named Dispatches in the database with 7 columns namely id, CustomerName, DispatchDate, DeliveryTime, Price and, Location with description as shown below:+--------------+--------------+------+-----+---------+-------+ | Field        | Type         | Null | Key | Default | Extra | +--------------+--------------+------+-----+---------+-------+ | ProductName  | varchar(255) | YES  | UNI | NULL    | | | CustomerName | varchar(255) | YES  |     | NULL    | ... Read More