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Programming Articles
Page 2518 of 2547
What is a hit count for a Webpage?
A hit counter tells you about the number of visits on a particular page of your web site. Usually, you attach a hit counter with your index.jsp page assuming people first land on your home page.To implement a hit counter you can make use of the Application Implicit object and associated methods getAttribute() and setAttribute().This object is a representation of the JSP page through its entire lifecycle. This object is created when the JSP page is initialized and will be removed when the JSP page is removed by the jspDestroy() method.Following is the syntax to set a variable at the ...
Read MoreHow to change the datatype of a column in an existing table using JDBC API?
You can change the datatype of a column in a table using the ALTER TABLE command.SyntaxALTER TABLE Sales MODIFY COLUMN column_name column_new_datatuypeAssume we have a table named Sales in the database with 7 columns namely ProductName, CustomerName, DispatchDate, DeliveryTime, Price, Location and, ID with description as:+--------------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------------+--------------+------+-----+---------+-------+ | ProductName | varchar(255) | YES | | NULL | | | CustomerName | varchar(255) | YES | | NULL ...
Read MoreRTTI (Run-time type Information) in C++
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 MoreC++ Program to Apply DFS to Perform the Topological Sorting of a Directed Acyclic Graph
Topological sorting of DAG (Directed Acyclic Graph) is a linear ordering of vertices such that for every directed edge uv, where vertex u comes before v in the ordering. If the graph is not a DAG, Topological Sorting for a graph is not possible.Functions and pseudocodesBegin function topologicalSort(): a) Mark the current node as visited. b) Recur for all the vertices adjacent to this vertex. c) Push current vertex to stack which stores result. End Begin function topoSort() which uses recursive topological sort() function: a) Mark all the vertices which are not visited. ...
Read MoreHow can you implement hit counter to avoid loss of count data with each restart of the application in JSP?
When you restart your application, i.e., web server, this will reset your application variable and your hit counter will reset to zero. To avoid this loss, consider the following points −Define a database table with a single count, let us say hitcount. Assign a zero value to it.With every hit, read the table to get the value of hitcount.Increase the value of hitcount by one and update the table with the new value.Display the new value of hitcount as a total page hit counts.If you want to count hits for all the pages, implement above logic for all the pages.
Read MoreLongStream mapToObj() method in Java
The LongStream mapToObj() method is used in Java to return an object-valued Stream consisting of the results of applying the given function to the elements of this stream.The syntax is as follows: StreammapToObj(LongFunction
Read MoreC++ Program to Check Whether a Hamiltonian Cycle or Path Exists in a Given Graph
A Hamiltonian cycle is a Hamiltonian Path such that there is an edge (in graph) from the last vertex to the first vertex of the Hamiltonian Path. It is in an undirected graph is a path that visits each vertex of the graph exactly once.Functions and purposes:Begin 1.function isSafe() is used to check for whether it is adjacent to the previously added vertex and already not added. 2. function hamiltonianCycle() solves the hamiltonian problem. 3. function hamCycle() uses hamiltonianCycle() to solve the hamiltonian problem. It returns false if there is no Hamiltonian Cycle possible, ...
Read MoreLongStream mapToDouble() method in Java
The mapToDouble() method returns a DoubleStream consisting of the results of applying the given function to the elements of this stream.The syntax is as follows:DoubleStream mapToDouble(LongToDoubleFunction mapper)The parameter mapper is a stateless function to apply to each element.To use the LongStream class in Java, import the following package:import java.util.stream.LongStream;The following is an example to implement LongStream mapToDouble() method in JavaExampleimport java.util.stream.LongStream; import java.util.stream.DoubleStream; public class Demo { public static void main(String[] args) { LongStream longStream = LongStream.of(5000L, 12000L, 15000L, 20000L, 25000L); DoubleStream s = longStream.mapToDouble(a → (double)a); System.out.println("Elements of DoubleStream..."); ...
Read MoreC++ Program to Check Whether it is Weakly Connected or Strongly Connected for a Directed Graph
Weakly or Strongly Connected for a given a directed graph can be find out using DFS. This is a C++ program of this problem.Functions usedBegin Function fillorder() = fill stack with all the vertices. a) Mark the current node as visited and print it b) Recur for all the vertices adjacent to this vertex c) All vertices reachable from v are processed by now, push v to Stack End Begin Function DFS() : a) Mark the current node as visited and print it b) Recur for all the vertices adjacent to this vertex ...
Read MoreWhat are the main classes and interfaces of JDBC?
JDBC API is available in two packages java.sql, core API and javax.sql JDBC optional packages. Following are the important classes and interfaces of JDBC.Class/interfaceDescriptionDriverManagerThis class manages the JDBC drivers. You need to register your drivers to this.It provides methods such as registerDriver() and getConnection().DriverThis interface is the Base interface for every driver class i.e. If you want to create a JDBC Driver of your own you need to implement this interface. If you load a Driver class (implementation of this interface), it will create an instance of itself and register with the driver manager.StatementThis interface represents a static SQL statement. ...
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