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Articles by karthikeya Boyini
Page 111 of 143
The Local Loop
In a telephone system, the local loop is a two-wire connection between the subscriber’s house and the end office of the telephone company. It is commonly referred to as the “last mile” of the telephone network. The loop may run from 1km to as far as 10 km.CompositionTraditionally, local loops are composed of twisted pair copper cables. The old local loops have several limitations − narrow bandwidth, high attenuation, distortion of symbols, crosstalk's etc.In recent times, copper wires are being replaced by fiber optic cables for faster and more accurate performance. Installation of fiber cables is popularly known as FttH ...
Read MoreC++ Program to Compute Combinations using Recurrence Relation for nCr
This is a C++ program to compute Combinations using Recurrence Relation for nCr.AlgorithmsBegin function CalCombination(): Arguments: n, r. Body of the function: Calculate combination by using the formula: n! / (r! * (n-r)!. EndExample#include using namespace std; float CalCombination(float n, float r) { int i; if(r > 0) return (n/r)*CalCombination(n-1,r-1); else return 1; } int main() { float n, r; int res; coutn; coutr; res = CalCombination(n,r); cout
Read MoreHow can I update and increment two fields in one command in MongoDB?
Let us first create a collection with documents −> db.incrementDemo.insertOne({"Value1":10, "Value2":20}); { "acknowledged" : true, "insertedId" : ObjectId("5cbdaf07de8cc557214c0e15") }Display all documents from a collection with the help of find() method. The query is as follows −> db.incrementDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cbdaf07de8cc557214c0e15"), "Value1" : 10, "Value2" : 20 }Following is the query to increment two fields in one command in MongoDB −> db.incrementDemo.update({}, { $inc : { Value1 : 1, Value2 : 1 } }); WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })Let us check both the fields ...
Read MoreHow can I use a script to create users in MongoDB?
You can use createUser() method for this. Following is the syntax −db.createUser( { user: "yourUserName", pwd: "yourPassword", roles: [ { role: "read", db: "yourDatabaseName" } ] } );Let us create a user in MongoDB. Here, we are using database ‘test’ −> db.createUser( ... { ... user: "David", ... pwd: "David123456", ... roles: [ { role: "read", db: "test" } ] ... } ... );This will produce the following output −Successfully added user: { "user" : "David", "roles" : [ { "role" : "read", "db" : "test" } ] }
Read MoreMongoDB shutdown option is unavailable? How to get it?
You need to switch the database to admin. Following is the syntax −use adminThe syntax is as follows for shutdown option −db.shutdownServer()Let us implement the above syntax for shutdown −> use admin switched to db admin > db.shutdownServer()This will produce the following output −server should be down... 2019-04-22T19:11:40.949+0530 I NETWORK [js] trying reconnect to 127.0.0.1:27017 failed 2019-04-22T19:11:42.197+0530 I NETWORK [js] reconnect 127.0.0.1:27017 failed failed
Read MoreConvert NumberLong to String in MongoDB?
In order to convert NumberLong to String in MongoDB, you can use toString() −NumberLong('yourValue').valueOf().toString();To convert NumberLong to String, you can use valueOf() as well −NumberLong('yourValue').valueOf();Let us implement both the above syntaxes.Following is the query to convert NumberLong to String with toString() −> NumberLong('1000').valueOf().toString();This will produce the following output −1000Following is the query to convert NumberLong to Number with valueOf()> NumberLong('1000').valueOf();This will produce the following output −1000
Read MoreCheck for Existing Document in MongoDB?
You can use findOne() for this. Following is the syntax −db.yourCollectionName.findOne({yourFieldName: 'yourValue'});Let us create a collection with documents −> db.checkExistingDemo.insertOne({"StudentName":"John"}); { "acknowledged" : true, "insertedId" : ObjectId("5cbdf90dac184d684e3fa265") } > db.checkExistingDemo.insertOne({"StudentName":"Carol"}); { "acknowledged" : true, "insertedId" : ObjectId("5cbdf912ac184d684e3fa266") } > db.checkExistingDemo.insertOne({"StudentName":"Sam"}); { "acknowledged" : true, "insertedId" : ObjectId("5cbdf916ac184d684e3fa267") } > db.checkExistingDemo.insertOne({"StudentName":"Mike"}); { "acknowledged" : true, "insertedId" : ObjectId("5cbdf91bac184d684e3fa268") }Display all documents from a collection with the help of find() method −> db.checkExistingDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cbdf90dac184d684e3fa265"), "StudentName" : "John" } { "_id" : ObjectId("5cbdf912ac184d684e3fa266"), "StudentName" : "Carol" } ...
Read MoreChange Color of Button in iOS when Clicked
Imagine you’re playing a song and as soon as you press the stop button, the color of the button should turn to red. This is one of the many scenario where you might need to change the color of button when it is clicked.In this tutorial we will see how to change the background color of a button when it is clicked. So let’s get started!Step 1 − Open Xcode → New Projecr → Single View Application → Let’s name it “ChangeButtonColor”Step 2 − In the Main.storyboard create one button and name it stop.Step 3 − Create @IBAction of the ...
Read MoreHow to get the Navigation Bar height in iOS?
A navigation bar appears at the top of an app screen. To read more about ithttps://developer.apple.com/designhttps://developer.apple.com/documentationGetting height of Navigation bar becomes important if you’ve multiple view controllers having different UI and requirement. It becomes hectic if you’re not aware how to get the height of the same or modify as per need. Let’s see how we can get the height of Navigation bar.import UIKit class ViewController: UIViewController { override func viewDidLoad() { super.viewDidLoad() let navBarHeight = UIApplication.shared.statusBarFrame.size.height + (navigationController?.navigationBar.frame.height ?? 0.0) print(navBarHeight) } }
Read MoreHow to answer incoming call programmatically in iOS?
Apple iPhone SDK doesn’t allow this feature. If you really wish to achieve it you can use some private api such as CTCallAnswer(call);This will result in your app store rejection.
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