In C++ and Java, there is another kind of loop, called the foreach loop. This is basically a modification of for loop. This loop is used to access the data from some container. This can access the elements of some array quickly without performing initialization. This loop is used to ... Read More

To select records having a given key, you can use $exists operator. The syntax is as follows −db.yourCollectionName.find( { yourFieldName: { $exists : true } } ).pretty();To understand the above syntax, let us create a collection with the document. The query to create a collection with a document is as ... Read More

Before getting into example, we should know what sqlite data base in android is. SQLite is an open source SQL database that stores data to a text file on a device. Android comes in with built in SQLite database implementation. SQLite supports all the relational database features. In order to ... Read More

In this section, we will see how to convert C++ string (std::string) to const char* or char*. These formats are C style strings. We have a function called c_str(). This will help us to do the task. It returns a pointer to an array that contains a null-terminated sequence of ... Read More

In C or C++, there are four different datatypes, that are used for integer type data. These four datatypes are short, int, long and long long. Each of these datatypes takes different memory spaces. The size varies in different architecture and different operating systems. Sometimes int takes 4-bytes or sometimes ... Read More

To remove NULL records in a column, you can use delete command. Following is the syntax −delete from yourTableName where yourColumnName IS NULL;Let us first create a table −mysql> create table removeNullRecordsDemo    -> (    -> Name varchar(100)    -> ); Query OK, 0 rows affected (0.50 sec)Following is ... Read More

In this program a random graph is generated for random vertices and edges. The time complexity of this program is O(v * e). Where v is the number of vertices and e is the number of edges.AlgorithmBegin    Develop a function GenRandomGraphs(), with ‘e’ as the    number of edges ... Read More

To aggregate sum in MongoDB to get the total count, you can use the $sum operator. To understand the above concept, let us create a collection with the document −> db.aggregateSumDemo.insertOne({"CustomerName":"Larry", "Amount":140}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c8baa0680f10143d8431e18") } > db.aggregateSumDemo.insertOne({"CustomerName":"Mike", "Amount":160}); {    "acknowledged" : true, ... Read More

This example demonstrates about How to remove data from HashSet in AndroidStep 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

In this section, we will see what is the at a () function in C++. The at() function is used to access the character at a given position.In this program, we will iterate through each character using at a () function and print them into different lines.Example Code Live Demo#include using ... Read More