What is C Programming? A Complete Guide

C Programming is a fast and efficient programming language that was originally created to develop the Unix operating system. It was created by Dennis Ritchie at Bell Labs in the 1970s.

Being a highly efficient language, it is used to create famous operating systems like Linux, Windows, and Mac and popular programming languages like Python, Java, Go, Ruby, PHP, and Javascript.

You can see that C programming powers the software world, and almost every system we use or build today has a direct or indirect connection with C programming.

But what exactly is C programming?

In this blog, we will discuss

the history of C programming,
reasons why you should learn C,
applications of C programming,
how C programming works, and
basic commands on C.

History of C Programming

Before jumping into all the dates and events, let’s first discuss why C programming was created.

Why was C Programming created?

C Programming was created to overcome the shortcomings of B programming.

B programming language was typeless, i.e., it did not have datatypes.
THe machines on which we first used B were word-address, and these language had a single datatype “cell”, which equated with the hardware machine word.
The advent of the PHP-11 exposed several inadequacies of B’s semantic model.
The character handling mechanism of B was clumsy.
It did not have good floating-point arithmetic that could be used in all relevant machines.
B compiler’s threaded code technique made programs so much slower.

These shortcomings of B programming made it impossible to build an operating system that required high speed and efficiency.

As an innovative fix, Dinnie Ritchie began to modify the B programming language to make it compatible to write code for an operating system. The modified B was the new C programming language.

Dates and Events

Now, let’s see the timeline of the development of different programming languages, which eventually led to the invention of the modern C programming language.

Date	Language Development	Developed By
1960	ALGOL	International Group
1967	BCPL, derived from ALGOL	Martin Richards
1970	B, derived from BCPL	Ken Thompson
1972	Traditional C, derived from B	Dennis Ritchie
1978	K&R C	Kernighan and Ritchie
1983	ANSI C	ANSI Committee
1990	ANSI / ISO C	ISO Committee
1999	C99	Standardization Committee

Even after C99, the language has been evolving to this day.

C also inspired other languages like JavaScript, PHP, and Java has made an incredible contribution to the tech world.

Why Learn C Programming?

Here are a few reasons why you should opt for learning C programming.

1. Beginner-Recommended Language

If you are a beginner and want to have a strong foundation in programming, learning C Programming can be a great way to start.

Here are the reasons why.

Learning C will help you understand the core concepts of programming, such as how variables and arrays are stored in the memory.
C does not have a garbage collector. Hence you have to take care of memory management yourself using a pointer. This helps you to understand the concept better.
C has fewer libraries. This means that you have to write code from scratch, which again helps you sharpen your programming skills.
C grants you greater access to computer hardware. So learning it can give you a deep understanding of how the software interacts with the machine.

In terms of simplicity, there are definitely easier languages than C, such as Python. But it cannot provide you with a deeper level of computer science concepts like C.

2. Job Scope of C Programming

Apart from enhancing your computer science skills, C also has pretty cool job opportunities.

Here are the researched data from Indeed and Stack Overflow.

Job Opening: 1,244

Annual Salary: $67,186

Companies that use C:

Top companies like Google, YouTube, and Apple use C for various reasons. According to Career Karma, here is a list of C companies, along with the salary of each profession.

Companies that use C	Used By	Average Annual Salary
Apple	Software Data Engineer Senior Software Engineer System Architect	$148,747 $187,390 $204,623
Facebook	Software Engineer Manager Hardware Platforms Architect System Validation Engineer	$148,640 N/A N/A
Google	Software Engineer Hardware Engineer Engineer Manager	$162,465 $163,925 $234,450
Microsoft	Software Engineering Lead Senior Electrical Engineer	$171,929 $183,283
Telegram Messanger	Software Engineers Site Reliability Engineer	N/A N/A
YouTube	Principal Engineer Web solutions Engineer Staff software Engineer	$186,649 $132,588 $148,774

As you can see, you can work on top companies with your C programming skills.

And since there are only a few C programmers (compared to Python or JavaScript), there will be less competition and high demand.

3. Applications of C Programming

The wide use of C programming is another reason for you to learn C. It is used to develop:

Operating Systems – Windows, Mac, Linux, iOS, and Android

Compilers – Python interpreter

Databases – Oracle, MySQL, and PostgreSQL are based on C

Game Engines – IW engine (used in Call of Duty), Unreal Engine 4 (used by Fortnite and Star Wars)

Graphical User Interface (GUI) – Adobe Photoshop and Illustrator

Embedded Systems – Microwaves, Heated Seats, Climate Control Systems, etc.

Browsers – Google Chrome and File System, Mozilla Firefox, and Thunderbird

How Does C Programming Language Work?

Since C programming is a mid-level programming language, the computer does not understand the code written in C.

So when we write C code, the computer has to execute the code multiple times to make it machine-readable.

Let’s see an example demonstrating the process:

1. Write C code in any editor. For example,

#include <stdio.h>

int main() {
    printf("Hello World");
    return 0;
}

Save this code with .c extension. For example, greet.c

The above code is not a machine code(0s and 1s). So the computer cannot understand it.

2. The code needs to be converted into 0s and 1s for machines to understand. To convert C code into machine code, there is a program called a compiler.

Compilers convert the source code into machine code in the following ways:

First, the greet.c file is preprocessed into greet.i file where all the comments are removed, and expansion of included files takes place.

Now, the greet.i is ready for compilation. After compilation, the compiled output is stored in greet.s.

The greet.s is the assembly-level instruction. The greet.s is assembled by an assembler and converted into machine-level instructions. The machine-level instructions are stored in greet.o.

The greet.o doesn’t have the function calls resolved. So the greet.o file is passed to the linker, which finally produces the executable file greet.exe.

Now, the greet.exe is executed, and the expected output, “Hello World” is printed on the screen.

Note that these are all handled by the compiler, so you do not need to worry about the process. It is just for your basic understanding of how things work around.

Basic Commands in C Programming

Let’s take an example of a simple C program.

#include <stdio.h>

int main() {
    printf("Hello World");
    return 0;
}

Now let’s break down the lines and understand what each command does.

C Commands	Function of the Command
#include <stdio.h>	imports the header file stdio.h that define a variety of input-output functions
int main()	denotes the starting point of the program
{..}	denotes the start and end of a function
printf()	in-built print function that comes under stdio.h header file
return 0	exit status of the function

These are the minimal commands required to run even a simple program in C.

Now, let’s dive into other concepts of C programming.

Basic Concepts of C Programming

Variable

A variable in programming is used to store data. For example,

int number = 20;

Here, number is a variable that holds the value 20.

Datatype

In the above code, the int is the data type of the variable number.

This means the variable number cannot store a value other than an integer number.

In C, every variable is associated with a data type. Similarly, every data type has a unique format specifier.

Let’s see the list of commonly used data types with their respective format specifier in C.

Data Type	Format Specifier
int	%d, %i
char	%c
float	%f

Take Input From User

In the previous example, we used the printf() function provided by stdio.h header file to print the message.

Similarly, we use the scanf() function to take input from the user. For example,

scanf("%d", number);

The code takes an integer input from the user and stores it in the number variable.

Note that we need to import the stdio.h file using #include<stdio.h> before we can use printf() and scanf() functions.

C Program to Take Two Input Numbers and Add Them

#include <stdio.h>

int main() {

    // initialize integer variables
    int number1, number2, sum;

    // printf("Enter two numbers:");

    // takes input from user using scanf()
    scanf("%d %d", &number1, &number2);
    
    // adds two inputs and store it in sum 
    sum = number1 + number2;
    
    // prints the sum
    printf("Sum is %d", sum);

    return 0;
}

Output

Enter two numbers: 10 5
Sum is 15

Here, we have used %d format specifier inside the scanf() function to take integer input from the user.

When the user enters integers, it is stored in the number1 and number2 variables. Then the printf() function prints the sum of two numbers.