PointersPointers are used to store the address of variable.SyntaxType *pointer;InitializationType *pointer; Pointer = variable name;Functionspointers are used to store address of variable.pointers can have a null value assigned.pointer can be referenced by pass by reference.a pointer has its own memory address and size on the stack.Example Live Demo#include using namespace ... Read More

To concatenate fields, use the $concat operator. Let us first create a collection with documents −>db.concatenateFieldsDemo.insertOne({"StudentFirstName":"Adam", "StudentLastName":"Smith"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd6ebf46d78f205348bc62e") } >db.concatenateFieldsDemo.insertOne({"StudentFirstName":"John", "StudentLastName":"Doe"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd6ebfc6d78f205348bc62f") } >db.concatenateFieldsDemo.insertOne({"StudentFirstName":"David", "StudentLastName":"Miller"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd6ec376d78f205348bc630") ... Read More

Use typeof to find datatype of all the fields −typeof db.yourCollectionName.findOne().yourFieldName;Let us first create a collection with documents −> db.findDataTypeDemo.insertOne({"ClientName":"Chris", "isMarried":false}); {    "acknowledged" : true,    "insertedId" : ObjectId("5ccf2064dceb9a92e6aa1952") }Following is the query to display all documents from a collection with the help of find() method −> db.findDataTypeDemo.findOne();This will ... Read More

The getopt() is one of the built-in C function that are used for taking the command line options. The syntax of this function is like below −getopt(int argc, char *const argv[], const char *optstring)The opstring is a list of characters. Each of them representing a single character option.This function returns ... Read More

The segmentation error is one of the runtime error, that is caused because of the memory access violation, like accessing invalid array index, pointing some restricted address etc. In this article, we will see how to detect this type of error using the GDB tool.Let us see the code and ... Read More

Prepend string to entire column in MongoDB using aggregate framework. Let us first create a collection with documents −> db.prependDemo.insertOne({"StudentFirstName":"John"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5ccf3bcedceb9a92e6aa1955") } > db.prependDemo.insertOne({"StudentFirstName":"Chris"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5ccf3bd3dceb9a92e6aa1956") } > db.prependDemo.insertOne({"StudentFirstName":"Robert"}); {    "acknowledged" : true,   ... Read More

Here we will see three functions. These functions are Rint(), rintf() and the rintl(). These functions are used to convert floating point values into rounded format.The rint() FunctionThis function is used for rounding floating point value to integer. The syntax is like below. If the result is outside of return ... Read More

This example demonstrate about How to start an Android activity when use clicks on NotificationStep 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.   ... Read More

Let us first create a collection with documents −>db.decrementingOperationDemo.insertOne({"ProductName":"Product-1", "ProductPrice":756}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd7a8ae6d78f205348bc63c") } >db.decrementingOperationDemo.insertOne({"ProductName":"Product-2", "ProductPrice":890}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd7a8b86d78f205348bc63d") } >db.decrementingOperationDemo.insertOne({"ProductName":"Product-3", "ProductPrice":994}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cd7a8c66d78f205348bc63e") } >db.decrementingOperationDemo.insertOne({"ProductName":"Product-4", "ProductPrice":1000}); {    "acknowledged" : ... Read More

In C++11, the lambda was introduced. Lambdas are basically a part of code, that can be nested inside other function call statements. By combining lambda expressions with the auto keyword, they can be used later.In C++14, these lambda expressions are improved. Here we can get the generalized lambda. For example, ... Read More