In C, we get the qsort() function. This is used to sort some array using quicksort technique. In this function we have to pass the comparator function. This comparator function takes two arguments. Then compares them and get the relative order between them. These two arguments are pointers, and type ... Read More

Let us first create a collection with documents −> db.excludeIdDemo.insertOne({"StudentFirstName":"John", "StudentAge":21}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd701a56d78f205348bc632") } > db.excludeIdDemo.insertOne({"StudentFirstName":"Robert", "StudentAge":20}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd701af6d78f205348bc633") } > db.excludeIdDemo.insertOne({"StudentFirstName":"Chris", "StudentAge":24}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd701b86d78f205348bc634") }Following is the query ... Read More

You can use positional operator $ for this. Let us first create a collection with documents −> db.subElementQueryingDemo.insertOne( ...    { ...       "ClientName":"Chris", ...       "Status": [ { "isMarried": true }, { "isMarried": false } ] ...    } ... ); {    "acknowledged" : ... Read More

To create high precision timer we can use the chrono library. This library has high resolution clock. This can count in nanoseconds.In this program we will see the execution time in nanoseconds. We will take the time value at first, then another time value at the last, then find the ... Read More

Yes, you can achieve this using aggregate framework. Let us first create a collection with documents −> db.sliceOfSliceDemo.insertOne( ...    { ...       "Name": "John", ...       "Details": [["First 1:1", "First 1:2"], ["second 2:1", "Second 2:2"]] ...    } ... ); {    "acknowledged" : true, ... Read More

Use the getChildCount() method in Java to get the count of child nosed of any node i.e. even if it’s a root node or not.Let’s say we want the count of child nodes for node 1, which is not a root node, therefore −node1.getChildCount()The following is an example to get ... Read More

Here we will see how to create self-destructing code in C. The self-destructing code is basically executing the code, and then remove the executable file after executing it.This task is very simple. We need to get the executable file name to remove it. We can use the command line arguments. ... Read More

Use $addToSet operator to update array element. Let us first create a collection with documents −> db.updateArrayDemo.insertOne( ...    { ... ...       "ClientDetails" : [ ...          { ...             "ClientName" : "John", ...           ... Read More

This example demonstrate about How to schedule notification in android.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. Step 3 − Add the following code ... Read More

Yes, you can use the findOne(). Following is the syntax −db.yourCollectionName.findOne();You can use toArray() as well −db.yourCollectionName.find().toArray();Let us first create a collection with documents −> db.betterFormatDemo.insertOne({"StudentName":"Adam Smith", "StudentScores":[98, 67, 89]}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd7ab826d78f205348bc640") } > db.betterFormatDemo.insertOne({"StudentName":"John Doe", "StudentScores":[67, 89, 56]}); {    "acknowledged" : ... Read More