Programming Articles - Page 2707 of 3363

In this section we will see what is the RTTI (Runtime Type Information) in C++. In C++ the RTTI is a mechanism, that exposes information about an object’s datatype during runtime. This feature can be available only when the class has at least one virtual function. It allows the type of an object to be determined when the program is executing.In the following example the first code will not work. It will generate an error like “cannot dynamic_cast base_ptr (of type Base*) to type ‘class Derived*’ (Source type is not polymorphic)”. This error comes because there is no virtual function ... Read More

The fork() function creates a new process by duplicating the current one. It allows developers to perform parallel tasks and manage resources efficiently. When fork() is called, it returns a value. If the value is greater than 0, then it is in the parent process. Otherwise, it is in the child process. In this C++ article, we will learn how to use the fork() system call to perform calculations in parent and child processes.According to the problem statement, we will do calculations. So, in our parent process, we will find the sum of all even numbers in an array, and ... Read More

In this section we will see how to use the fork() to make child process in C. We also do some different tasks in each process. So in our parent process we will print different values.When fork() is called, it returns a value. If the value is greater than 0, then currently it is in parent process, otherwise it is in child process. So using this we can distinguish between the processes.Example Code#include #include int main() {    int n = fork(); //subdivide process    if (n > 0) { //when n is not 0, then it is ... Read More

The CachedRowSet is the base implementation of disconnected row sets. It connects to the data source, reads data from it, disconnects with the data source and the processes the retrieved data, reconnects to the data source and writes the modifications.You can create a Cached RowSet object using the createCachedRowSet() method of the RowSetFactory.You can create a RowSetFactory object using the newfactory() method of the RowSetProvider method.Updating a Particular column of a rowThe updateXXX() methods of the CachedRowSet interface allows you to update column values of a particular row in a RowSet object.Get the required row and update the desired column ... Read More

The CachedRowSet is the base implementation of disconnected row sets. It connects to the data source, reads data from it, disconnects with the data source and the processes the retrieved data, reconnects to the data source and writes the modifications.Creating a CachedRowSetYou can create a Cached RowSet object using the createCachedRowSet() method of the RowSetFactory.You can create a RowSetFactory object using the newfactory() method of the RowSetProvider method.Create a CachedRowSet object using the above mentioned methods as shown below −//Creating the RowSet object RowSetFactory factory = RowSetProvider.newFactory(); CachedRowSet rowSet = factory.createCachedRowSet();Connecting to the data sourceAfter creating a RowSet object you ... Read More

The CachedRowSet is the base implementation of disconnected row sets. It connects to the data source, reads data from it, disconnects with the data source and the processes the retrieved data, reconnects to the data source and writes the modifications.Creating a CachedRowSetYou can create a Cached RowSet object using the createCachedRowSet() method of the RowSetFactory.You can create a RowSetFactory object using the newfactory() method of the RowSetProvider method.Create a CachedRowSet object using the above-mentioned methods as shown below −//Creating the RowSet object RowSetFactory factory = RowSetProvider.newFactory(); CachedRowSet rowSet = factory.createCachedRowSet();Connecting to the data sourceAfter creating a RowSet object you need ... Read More

A RowSet object is similar to ResultSet, it also stores tabular data, in addition to the features of a ResultSet. A RowSet follows the JavaBeans component model.If you Retrieve a ResultSet object by default the cursor of it moves only in forward direction. i.e. you can retrieve the contents of it from first to last.But, in a scrollable result set, the cursor can scroll forward and backward and you can retrieve data backward too.To make ResultSet object scrollable, you need to create one as shown below −Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE);Whereas, a RowSet object is Scrollable by default. Therefore, whenever ... Read More

A RowSet object is similar to ResultSet, it also stores tabular data, in addition to the features of a ResultSet a RowSet follows JavaBeans component model. This can be used as a JavaBeans component in a visual Bean development environment, i.e. in environments like IDE’s you can visually manipulate these properties.Connecting RowSet with databaseThe RowSet interface provides methods to set Java bean properties to connect it to the required database −void setURL(String url):void setUserName(String user_name):void setPassword(String password):PropertiesA RowSet object contains properties and each property have Setter and getter methods. Using these you can set and get values from a command ... Read More

In this article, we implement a C++ program to print a hollow pyramid and diamond pattern. We can create solid Pyramid patterns easily using a loop. To make it hollow, we have to add a few logics. Hollow Pyramid A hollow pyramid is a pattern where a pyramid shape is formed, but only the outer edges (the borders) are filled with characters, while the interior is left empty. Let's explain how we can create hollow pyramid − The first line prints only one star (*). The last line (i.e., the ... Read More

std::reference_wrapper is a class template in C++ that allows you to store references to objects or functions in a way that makes them copyable and assignable. Normally, C++ references can't be stored in standard containers like std::vector or std::list, because references are not copyable. std::reference_wrapper solves this problem by internally storing a pointer to the referenced object. It acts like a wrapper around a reference and behaves almost like the original object. It can be passed to functions that take T& (a reference to T), because std::reference_wrapper is implicitly convertible to T&. This is especially useful when you ... Read More