C Programming - Tutorial

C Programming - Tutorial

  January 20, 2022    Digital Scroller

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What is Programming?

Computer programming is a medium for us to communicate with computers, just like we use Hindi or English to communicate with each other. Programming is a way for us to deliver our instructions to the computer

What is C programming?

C is a programming language. C is one of the oldest and finest programming languages. C was developed by Dennis Ritchie in 1972.

Uses of C

C is a language that is used to program a wide variety of systems. Some of the uses of C are as follows:

Major parts of Windows, Linux, and other operating systems are written in C.
C is used to write driver programs for devices like Tablets, Printers, etc.
C language is used to program embedded systems where programs need to run faster in limited memory.
C is used to develop games, an area where latency is very important, i.e., a computer has to react quickly to user input.

Chapter 1: Variables, Constants, and Keywords:

Variables

A variable is a container that stores a ‘value.’ In the kitchen, we have containers storing rice, dal, sugar, etc. Similar to that variable in c stores the value of a constant. Example:

a = 3	a is assigned “3”
b = 4.7	b is assigned “4.7”
c = 'A'	c is assigned “A”

Rules for naming variables in C :

1. The first character must be an alphabet or underscore(_).

2. No commas or blanks are allowed.

3. No special symbol other than underscore is allowed

4. Variable names are case sensitive

Constants

An entity whose value doesn’t change is called a constant.
Types of constant

Primarily there are 3 types of constant:

1. Integer Constant	-1,6,7,9
2. Real Constant	-322.1,2.5,7.0
3. Character Constant	‘a’,’$’,’@’(must be enclosed within single inverted commas)

Keywords

These are reserved words whose meaning is already known to the compiler. There are 32 keywords available in C programming:

auto	double	int	struct
break	long	else	switch
case	return	enum	typedef
char	register	extern	union
const	short	float	unsigned
continue	signed	for	void
default	sizeof	goto	volatile
do	static	if	while

Our first C program

#include<stdio.h>

int main() {

printf(“Hello World”);
return 0;

}

File : first.c

The basic structure of a C program

All c programs have to follow a basic structure. A c program starts with the main function and executes instructions presents inside it. Each instruction terminated with a semicolon(;)

There are some basic rules which are applicable to all the c programs:

1. Every program's execution starts from the main function.
2. All the statements are terminated with a semi-colon.
3. Instructions are case-sensitive.
4. Instructions are executed in the same order in which they are written.

Comments

Comments are used to clarify something about the program in plain language. It is a way for us to add notes to our program. There are two types of comments in c:

1. Single line comment: //This is a comment.
2. Multi-line comment : /*This is multi-line comment*/

Note: Comments in a C program are not executed and ignored.

Compilation and execution

A compiler is a computer program that converts a c program into machine language so that it can be easily understood by the computer.

A program is written in plain text. This plain text is a combination of instructions in a particular sequence. The compiler performs some basic checks and finally converts the program into an executable.

Library functions

C language has a lot of valuable library functions which is used to carry out a certain task; for instance, printf function is used to print values on the screen.

Types of variables

Integer variables	int a=3;
Real variables	int a=7.7 (wrong as 7.7 is real) ; float a=7.7;
Character variables	char a=’B’;

Chapter 2: Instructions and Operators:

A C-program is a set of instructions. Just like a recipe - which contains instructions to prepare a particular dish.

Types of instructions in C:

1. Type declaration instruction
2. Arithmetic instruction
3. Control instruction

Type of declaration instruction:

int a;
float b;

other variations:

int i = 10; int j = i, int a = 2;
int j1 = a + j - i;

float b = a+3; float a = 1.1;    ==>Error! As we are trying to use a before defining it. 

int a,b,c,d;

a=b=c=d=30;                      ==> Value of a,b,c & d will be 30 each. 

Arithmetic Instructions

Note:

1.No operator is assumed to be present

int i=ab ( Invalid )

int i=a*b ( valid )

2. There is no operator to perform exponentiation in c however we can use pow(x,y) from <math.h> (More in next chapter).

Type conversion

An Arithmetic operation between

int and int     ==> int
int and float   ==> float
float and float ==> float

5/2 --> 2               5.0/2 --> 2.5 //IMPORTANT!!
2/5 --> 0               2.0/5 --> 0.4 //IMPORTANT!!

NOTE:
int a = 3.5; //In this case, 3.5 (float) will be denoted to a 3 (int) because a cannot store floats.

float a = 8; // a will store 8.0 [8-->8.0(Promotion to float)]

Quick Quiz:

Question - int k=3.0/9 value of k? and why?

Solution - 3.0/9=0.333, but since k is an int, it cannot store floats & value 0.33 is demoted to 0.

Operator Precedence in C

3*x-8y is (3x)-(8y) or 3(x-8y)?

In the c language, simple mathematical rules like BODMAS no longer apply.

The answer to the above question is provided by operator precedence & associativity.

Operator precedence

The following table list the operator priority in C.

Priority	Operators
1st	* / %
2nd	+   -
3rd	=

Operators of higher priority are evaluated first in the absence of parenthesis.

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Is Solana the real Ethereum killer?

Is Solana the real Ethereum killer?

  September 11, 2021    Digital Scroller

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Solana is one of the fastest-growing cryptocurrencies in the crypto market. It has performed nicely to replace Ethereum in the coming years, According to the market analysis, it is found that its price will not increase as much as Ethereum but definitely, it can replace Ethereum in Ranking. 

Most of the investors and traders are not accepting Ethereum because of its high fee in transactions and its latency at the same time Solana project is creating hype because it is much faster in transactions than Ethereum with a low transaction fee.

Solana is currently competing with Binance Coin, Polkadot, and Tether in the market. It has left many cryptocurrencies behind in the crypto market just because of its fast secure and open structure, many of project has adapted Solana chain and its market expansion is increasing day by day.

How Solana Is Ranking?

Leaving behind many of the cryptocurrencies Solana is now in the top 10 and has taken 6th rank in the cryptocurrency market. Its current price is $182 and the price is continuously rising.

Should We Invest In Solana?

As if now, it is the perfect time to invest in Solana, currently it's rising per day so it can be a good time to invest and hold for a long time. It is also the fastest-growing ecosystem in the crypto market with over 400 projects.  

Digital Scroller does not bear any responsibility for their advice. Please consult your financial advisor before dealing/investing in cryptocurrencies.

Transaction speed 

If we compare it with Ethereum, then Ethereum is completing only 15 transactions per sec and BSC is completing 100 per sec, and Polkadot per 1000 per sec but Solana is completing 65000 per sec that is super fast. If we compare its transaction speed then it is again the lowest.

Transaction Fees 

Ethereum - 30-80$ per trasaction 

Polkadot - $1 per trasaction 

Binance Smart chain  - $0.01 per trasaction 

Tron - Free

Solana - $0.00025 per transaction

Conclusion

When Solana is skyrocketing that much faster in the cryptocurrency market than it may take over Ethereum's market and its projects. Traders and investors are moving towards Solana instead of Ethereum for smart contracts, You need not wonder to invest in Solana, have a market analysis first then you can invest in this.

Do you think Solana is an Ethereum killer? Comment your answer!

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What is an API | Application programming Interface

What is an API | Application programming Interface

  August 22, 2021    Digital Scroller

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API

When you hang around programmers, you might have heard about APIs and how they can be

used to perform certain tasks or retrieve some data ,But what are these exactly, and why were they created?

Let me explain the problem with a simple, non-IT related example.

When you go to a restaurant and order some food, you interact with the waiter. You can order food and drinks, ask questions about the menu, request and pay the bill, and much more.

In this example, the waiter is shielding you from all the complicated stuff that happens

behind the scenes. you don’t have to worry about stoves, ovens, dishes, managing stock, or pouring drinks.

He is the interface between you and all of the services that a restaurant offers. Giving you a way to interact with the restaurant while still shielding you from all the complexity behind the scenes. In a way, the waiter can be seen as the API of the restaurant, and through this example, you intuitively understand why they are useful.

The term API stands for Application Programmable Interface, and it’s a way for different programs to work together in various ways. There are many types of API’s and reasons why they are used.

I’ll highlight 4 of them here:

For starters, API’s can be used to get access to data from third parties. In the restaurant example, the waiter can provide you information on the status of your order, without you having to go to the kitchen yourself. 

Another example would be the weather app on your phone. Google or Apple have not gone out and put temperature sensors all over the world. No, instead these apps use the API of a third-party to retrieve weather predictions. Apple for instance is using the API of The Weather Channel.

API’s allow different apps and services to exchange information. These days, it’s hard to find a service that doesn’t have an API. There are API’s to lookup recipes, lyrics, information on barcodes, zip codes, available parking spaces, public holidays, and so on and so on.

Aside from just accessing data, API's can also be used to hide complexity and perform tasks.

In the restaurant example, you don’t need to know how to prepare a perfect roll of Sushi,

you just order one. 

Another example would be the operating systems on our computers and phones. App developers don’t have to worry about setting up a WiFi connection, drawing shapes onto the screen to make a beautiful user interface or how to talk to the various sensors like the accelerometer or GPS.

No, instead the operating system gives developers a bunch of API’s that simplify all of this. If an app wants to show a button on the screen, it just asks the system to render one. The app doesn’t have to worry about what device it is running on, what hardware it has, screen resolution, or anything like that.

It makes developers more efficient because they can focus on what matters to them.

But aside from accessing data and abstracting complexity, API's can also be used to extend

functionality. For instance, on iOS, applications can show a widget in Notification Center.

And to do that, the app notifies the system through an API that it has a widget available.

And if the user adds it to their Notification Center, the system will contact the app to

ask how it should display the widget.

Another example is Siri, Google Assistant or Alexa. These personal assistants are quite clever but external developers can use the assistant’s API to extend the functionalities even further.

Google Home

My Google Home for instance didn’t know how to turn my smart plugs on and off.

But that changed, when the vendor integrated with the Google Assistant through its API.

Suddenly, Google became aware of the new hardware, its capabilities and how to interact with

them.

You might not realize it, but API’s are all around us. You’ve probably seen messages like these, your phone asking for permission to use your location or microphone. That brings us to the final use case: API’s can be used as gatekeepers.

For instance, on mobile platforms, the system only has a handful of API’s that can be

used to get your location. And because it’s centralized in the system, it’s really easy for iOS or Android to notify you when an app is using your location. So it’s not the app that is being nice, and asks permission first. No, it’s the system that does it for them.

There’s no way around it. What’s more, the system also gives the ability to revoke this permission at a later time, should you change your mind.

So every time your phone asks you for permission, you know that an app is using an API of the

system. And one that is privacy sensitive. And while that is great, there is an issue with this usually permission is only asked once

.

You might have used your Google or Facebook account to login to another website or app.

It’s easy, fast and convenient. But by doing that, we also give the website or app the permission to access some of our data. Like our name or email address.

This is great, because it puts us in control of our personal data. if you don’t want to share it, you just deny it. However, the problem here is that sometimes these permissions are long lasting and after

a while we forget what apps or websites we gave permission to access our data. This is what allowed Cambridge Analytica to collect massive amounts of data through the Facebook API.

They created a “personality quiz” that asked for permission to get some of your personal

data. However, if you gave it permission, the app could silently access your data for months,

even if you didn’t use it anymore.

Instead, you had to revoke the permission through the Facebook website. So, in short: API’s can act as gatekeepers, protecting our personal data and only giving it out to the apps we choose.

But we should be aware about how long those permissions last, and revoke them when we

no longer use an app. So time for a conclusion. API’s are all around us.They are used to get access to data so that multiple apps or services can work together.They can also hide complexity for developers, allowing them to not waste time on figuring out how GPS works for instance.

API’s can also be used to extend functionality of existing systems and finally, they can

act as gatekeepers to protect our personal data.

I hope this article brought some clarity to a topic that is mostly discussed among developers.

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