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Articles on Trending Technologies
Technical articles with clear explanations and examples
C++ 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 MoreWorking with dates before 1970 in MySQL?
You need to use date type to work with date before 1970 because date stores value from 1000 to 9999. A date type can be used when you need to work with date part only not for time purpose.MySQL gives the data in the following format. The format is as follows −‘YYYY-MM-DD’The starting date range is as follows −1000-01-01The ending date range is as follows −9999-12-31To understand what we discussed above, let us create two tables. The query to create first table is as follows −mysql> create table DateDemo -> ( -> Id int ...
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 MoreIs it possible to enforce data checking in MySQL using Regular Expression?
Yes, it is possible to enforce data checking in MySQL using regular expression. First, you need to create a table. After that you need to create a trigger before insert in table. Here, we will be checking the Phone Number format.The query to create a table is as followsmysql> create table enforceDataUsingRegularExpression - > ( - > yourPhoneNumber varchar(60) - > ); Query OK, 0 rows affected (0.59 sec)The query to create a trigger is as followsmysql> DELIMITER // mysql> CREATE TRIGGER enforce_phone_check BEFORE INSERT ON enforceDataUsingRegularExpression - ...
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 MoreHow to resize an UIImageView using Swift?
To resize an image in iOS using swift we’ll make use of frame.Let’s see this with help of an example.Create an empty project and add an empty Image view.Create its outlet.Add an image to your project and assign the image to image view.Initially when we run the application, it looks something like this.Now, let’s add code to resize the image.override func viewWillLayoutSubviews() { let frame = CGRect(x: 10, y: 10, width: self.view.frame.width - 20, height: 300) self.imgView.frame = frame }We will run this code in our viewWillLayoutSubviews method. This is how it looks on the device when we ...
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 MoreHow do you hide the onscreen keyboard in iOS App?
To hide a keyboard on screen we need to make use of some internal functions that are predefined in the iOS SDK. The keyboard appears on screen when we are typing in a text Field or textView. We need to make use of internal function according to the text field.For example if the current text field is tfOne, we can hide the text field using the code below:tfOne.resignFirstResponder()This code will hide the keyboard when ever called, we may call this on an action for a button or for gesture recognizer.This method is good for limited textFields, but we need to ...
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