The Pointer in C is a variable that stores the address of another variable. A pointer can also be used to refer to another pointer function. A pointer can be incremented/decremented, i.e., to point to the next/ previous memory location. The purpose of a pointer is to save memory space and achieve faster execution time.

Different Ways of Accessing Variable Address in C

Let us try to know what are the different ways by which we can print the address of a variable in C.

There are two ways by which we can actually print the address of a variable. Those two methods are:

Let us look into each method with an example

In this method, we will be using the concept of the ampersand to print the address of a variable.

printf("The address of variable varNumValue: %x\n", &varNumValue  );

printf("varTextValue variable address is : %x\n", &varTextValue  );

Now, copy the above code snippet and run it

The address of variable varNumValue: a0665a48

The address of variable varTextValue is : a0665a3e

Although, one might see the different value which is assigned randomly while running the example

The above-mentioned example is not much used, but it is worth knowing. Now let us look to the other concept which we are discussing in this topic.

This is a modern approach to access the address of a variable. Before using a pointer, let us know the general syntax of declaring a pointer.

The general syntax of declaring a pointer – A common syntax which we use for declaring a variable is:

This is a common way to declare any pointer in C, here data_type represents the type of the variable whose address needs to be stored. * denotes that the variable declared is a pointer. a variable is simply used for accessing the value

After discussing the concept of the General syntax of declaring a pointer, let us know how we can use a pointer in programming.

To use a pointer in C, basically, one needs to follow the following three steps:

Assigning the address of the variable whose address we want to hold in the pointer variable

Now, once we have a pointer variable with the address, we can again retrieve the value of the variable from the address stored in the pointer. This could be done using is simply one of the unary operators in C.

Let us use the above-mentioned steps with an example, and then we will explain this example step by step.

printf("Address of the variable varNumValue is: %x\n", &varNumValue  );

printf("Address stored in the variable ipointervarNumValue is: %x\n", ipointervarNumValue);

printf("Value of the variable *ipointervarNumValue is: %d\n", *ipointervarNumValue );

Address of the variable varNumValue is: bf7b7f94

Address stored in the variable ipointervarNumValue is: bf7b7f94

Value of the variable *ipointervarNumValue is: 10

Now, let us try to understand the above example

The line int  varNumValue = 10; simply declares a variable with value 10

The second line that is a line next to it: int  * ipointervarNumValue; is simply declared to store the address of the variable

The next code snippet, which is: ipointervarNumValue = &varNumValue, is used to hold the address of the variable. Here, we are using the concept of an ampersand, which we discussed earlier in the article

Now, we can simply get the value and use a pointer in our code snippet

Now, let us look into different types of a pointer in C

Different types of pointers in C are following:

We can create a null pointer by assigning null value during the pointer declaration. This method is useful when you do not have any address assigned to the pointer. A null pointer always contains value 0.

Following program illustrates the use of a null pointer:

	printf(“The value inside variable p is:\n%x”,p);

In C programming, a void pointer is also called as a generic pointer. It does not have any standard data type. A void pointer is created by using the keyword void. It can be used to store an address of any variable.

Following program illustrates the use of a void pointer:

printf("The size of pointer is:%d\n",sizeof(p));

Today we'll discuss what a pointer is and what's its use.

Pointer in C

In modern web development, it is common to utilize cloud-based databases to store and retrieve data for web applications. Firebase, a popular Backend-as-a-Service (BaaS) platform, provides a real-time database that developers can leverage. In this blog post, we will explore how to assign Firebase database values to variables using JavaScript, enabling dynamic and responsive web applications.

Before diving into assigning Firebase database values to variables, ensure you have the following prerequisites:

Basic understanding of JavaScript programming.

Familiarity with Firebase and its real-time database.

A configured Firebase project with the necessary credentials.

To interact with the Firebase real-time database in JavaScript, we need to establish a connection to the database. Begin by including the Firebase SDK in your HTML file. You can either host the SDK file locally or include it from a content delivery network (CDN). Next, initialize Firebase with your project credentials using the Firebase configuration object.

Once the connection is established, you can retrieve data from the Firebase database. Use the appropriate Firebase SDK method, such as firebase.database().ref(), to reference the desired database node. For example, to retrieve the value of a node named "exampleNode," you can use the following code:

const databaseRef = firebase.database().ref('exampleNode');

databaseRef.once('value').then((snapshot) => {

The once('value') method retrieves the value of the specified node once. The resulting snapshot object contains the retrieved data, which can be accessed using the val() method. Assign the retrieved value to a variable, such as value in the code snippet, to utilize it further in your application.

Now that we have retrieved the database value, we can assign it to a JavaScript variable. Within the then callback of the once('value') method, you can simply assign the value to a variable of your choice. For example:

In this example, the retrieved value from Firebase is assigned to the myVariable variable. You can now manipulate and utilize this value within your JavaScript code as needed. Remember that Firebase queries and data retrieval are asynchronous, so ensure that any code depending on the assigned variable is executed within the then callback or by using asynchronous programming techniques such as Promises or async/await.

In this blog post, we explored the process of assigning Firebase database values to variables in JavaScript. By establishing a connection to the Firebase real-time database and using appropriate Firebase SDK methods, you can retrieve data from the database. Subsequently, by assigning the retrieved value to a JavaScript variable, you can use it for further processing and application logic. This ability to dynamically assign database values to variables enables the creation of responsive and data-driven web applications. With these techniques in your toolkit, you can harness the power of Firebase to build interactive web experiences.

This blog explains how to assign Firebase database values to variables in JavaScript, enabling dynamic and responsive web applications.

Assigning Firebase Database Values to Variables in JavaScript

How would you explain JavaScript closures to someone with a knowledge of the concepts they consist of (for example functions, variables and the like), but does not understand closures themselves?

I have seen the Scheme example given on Wikipedia, but unfortunately it did not help

How do JavaScript closures work?

What is the difference between a member variable and a local variable?

I need to use something like RxSwift 3.0 Variable, but in RxSwift 5.0, it's completely deprecated.

What is Variable subject alternative in Rxswift 5.1?

let overwatch = Game(price: Variable(value: 59.99))

In RxSwift 5.1 and later versions, it is recommended to use BehaviorRelay as an alternative to Variable. BehaviorRelay is a wrapper around BehaviorSubject that provides similar functionality. It is a subject that can be used both as an observable sequence and as an observer, allowing you to both read and modify its value.

Here's an example of using BehaviorRelay:

let relay = BehaviorRelay(value: "Initial value")

In the above example, the BehaviorRelay is created with an initial value of "Initial value". Then, we subscribe to its observable sequence and print any new values that are emitted. Finally, we use the accept method to update the value of the relay to "Updated value".

What is Variable subject alternative in RxSwift 5.1?

I discover myself continuously writing what I see as unnecessary code in ruby while using named arguments for techniques.

  # orange, lemon & grapefruit in this format which is way prettier & concise than 

  # args[:orange] args[:lemon] args[:grapefruit]

  puts "my_method variables: #{orange}, #{lemon}, #{grapefruit}" 

my_method :orange => "Orange", :grapefruit => "Grapefruit"

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