What is C Programming?

Features of C Programming

Loved by programmers for doing low-level coding and embedded programming, C has found its way gradually into the semiconductor, hardware, and storage industries. The most important features provided by the C programming languages include:

• It has inbuilt functions and operators that can solve virtually any complex problem
• C is the combination of both low level (assembly) and high-level programming languages; also, it can be used to write an application and interact with low-level system memory and hardware
• It can be written on practically any operating system and even works in most handheld devices
• Programs written in C are speedy due to the support provided by its datatypes and operators
• It is easily extendable, as C++ was derived from C with additions like OOPS and other features
• The functions and operators are supported by the libraries provided by the programming language itself

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C Program (“Hello World”)

#include <stdio.h>

#include <conio.h>

int main ()

{

int a = 1, b=2, c=0;

int c = a + b;

printf(“Hello World”);

printf(“C = “ %d, c);

return 0;

}

Preprocessor Directives

The #include in the first line of the C program is referred to as preprocessor directives. All of the preprocessors will start with the # symbol. It is the first line that is executed, having the library file ending with .h. The stdio.h in the above program will have libraries associated with print to the console output. This will also associate the program with the library. The compiler to transform the program before compilation will use the preprocessor. Macros are also similar to preprocessors, but they are all user-defined and help in expanding the values in all places in the program. 

For example:

#define AREA=354;

This will substitute the variable AREA with 354 everywhere in the program and requires less effort by the programmers in the event a change is needed in the future.

Header Files

There are some standard header files provided by the language, which can be used in the program to do mathematical or logical calculations or even print to the console or files. In the above example, you have used printf function, which prints the output to the console. The stdio.h header file will have relevant or associated code for printing the output to the console, so it has to be included upfront in the program for execution.

main() function

This is an important function in the C program within which the content of the program or logic or calculation will be written. The main can have return types, and in the above example, it has an integer as the return types. 

Compiling a C Program:

There are multiple ways to compile a C program. You can either use freely available editors provided by Turbo C. You can download the Turbo C editor over the internet; use it to write a program and compile using the Compile (Alt+ F9) option, and execute using Run (Ctrl + F9). The Turbo C editor is suitable for beginners, as the IDE is user-friendly. However, if you don’t have any IDEs (for example, if you’d like to execute a C program in Non-GUI environments like UNIX or Linux), you can use the following command:

$ gcc helloworld.c

$ . /a.out

Data Types

Data types are nothing but how the programmers enter, store, and manipulate data in the program. Like all other languages, C has a variety of data types, and they are mainly classified as primary datatypes, derived data types, and user-defined data types. 

Primary data types are the ones that are a fundamental part of C programming language and are mostly straightforward to use (they are int, char, float, and void). Int is used to hold whole numbers and can take values like zero, positive, or negative, but it can’t contain negative values. Float and double are used to hold real numbers, and they differ from each other in byte size. Similarly, int also can handle longer and shorter ranges, which are called short and long. The table below summarizes the different data types and the size each holds in memory.

The format specifier is dependent on the data type used in the program and is used to tell the compiler the type of data being processed during scanf and printf function. If the scanf has %d, then it is processing integer (int), and if it has %c, then it is processing character.

Derived data types are primitive data types forming new data structures called arrays, functions, and C pointers. For example, an array can contain a homogenous set of primitive data types like int, float, or double and can now act as a new data type in C programming language. Functions in C are both user-defined and standard library functions like scanf(), printf(), gets() and puts().

User-defined data types are defined by users and are usually a combination of data types or heterogeneous data types. For example, a structure may contain:

struct employee

 {

  char name[100];

  int empid;

  float salary;

 }

With the above structure in place, the user can now define a user-defined data type as follows:

struct employee info;

Operators in C

Operators are symbols used to perform mathematical or logical operations on data. The following is the category of operators present in C:

• Arithmetic Operators
• Relational Operators
• Logical Operators
• Bitwise Operators
• Ternary or Conditional Operators
• Assignment Operator

The precedence of the operators will specify which will be evaluated first. For example:

int a=10+10*30

The result of the above statement is 310 because the multiplication operator is evaluated first, followed by addition. 

Constants

Constants are different from variables, as the value can’t be changed during the due course of the program. There are different types of constants in the C programming language:

• Decimal
• Real or Floating Point
• Hexadecimal
• Octal
• Character
• String

Control Statements

Control statements are the ones that specify the program flow or the order in which the steps or instructions need to be executed. They perform the task of decision making, depending on the conditions specified in the program. There are four types of control statements in the C programming language:

1. Decision making
2. Selection
3. Iteration
4. Jump

Decision-making statements decide the flow of the program based on logical conditions like OR, AND, and NOT. The set of statements that are nested below the decision-making statements are executed based on the logical criteria met. The if and if-else (and nested if-else) are sets of decision-making statements in C.  

Selection statements are based on case switch keywords. If the condition specified in the case keyword is met, then the statements below the case will be executed, and else switch statements will be executed. Iterations statements (or loops) are statements that repeat the set of instructions present inside the blocks until the condition is met. The looping statements in C programming language are while, do-while, while do, and for loop. 

A counter is usually incremented or decremented inside the looping or iterative statements to make sure the loop exits when the condition is met. Jump statements are GOTO statements that can abruptly change the course of the program to execute different sets of statements mentioned in the GOTO statement. Generally, GOTO statements are not recommended in the program, as it would be difficult to predict the flow of the program in run time.

C Program to Find the Factorial of a Number

Now let’s see a small C program based on what we’ve learned above. The objective of the program is to print the factorial of any given number.

#include <stdio.h>

int main()    

{    

 int i,factorial=1,num=0;    

 printf("Enter the number for which the factorial need to be calculated? ");    

  scanf("%d",&num);    

    for(i=1;i<=numb;i++){    

      factorial=factorial*i;    

  }    

  printf("Factorial of the given number %d is %d",num,factorial);    

return 0; 

}  

Output

Enter the number for which the factorial needs to be calculated?

5

Factorial of the given number 5 is 120

Career Prospects in C Programming

Career prospects in C programming are diverse and abundant, offering opportunities in various industries and roles. As one of the oldest and most widely used programming languages, proficiency in C opens doors to a range of rewarding career paths. Here's an elaborate look at the career prospects in C programming:

Software Developer

Software developers proficient in C programming are in high demand across industries. They design, develop, test, and maintain software applications and systems using C. They work on a wide range of projects, from embedded systems and operating systems to large-scale enterprise applications.

Embedded Systems Engineer

C is the language of choice for embedded systems development due to its low-level capabilities and efficient memory management. Embedded systems engineers use C programming to develop firmware for microcontrollers, IoT devices, automotive systems, and consumer electronics.

System Programmer

System programmers specialize in writing software that interacts with the underlying hardware and operating systems. They use C to develop device drivers, kernel modules, system utilities, and system-level applications. System programmers play a crucial role in optimizing performance and ensuring the stability of computer systems.

Game Developer

C is widely used in the game development industry for its performance and control over hardware resources. Game developers leverage C to create game engines, graphics libraries, and game logic for a variety of platforms, including consoles, PCs, and mobile devices.

Firmware Engineer

Firmware engineers develop software that runs on embedded systems and electronic devices. They use C to write code that controls hardware components such as microcontrollers, sensors, and actuators. Firmware engineers work in industries like aerospace, automotive, medical devices, and consumer electronics.

Cybersecurity Specialist

With the rise of cybersecurity threats, there is a growing demand for professionals who can secure software systems and networks. Cybersecurity specialists proficient in C programming analyze code for vulnerabilities, develop security patches, and implement security protocols to protect against cyber attacks.

Technical Consultant

Technical consultants with expertise in C programming provide advisory services to businesses on software development, system architecture, and technology integration. They assess client requirements, design custom solutions, and offer technical guidance to optimize performance and efficiency.

Academic Researcher

In academia, researchers use C programming for theoretical and applied research in computer science, engineering, and mathematics. They develop algorithms, simulations, and numerical models to advance knowledge in various fields, such as artificial intelligence, computational biology, and scientific computing.

Quality Assurance Engineer

Quality assurance engineers test software applications and systems to ensure they meet quality standards and functional requirements. They use C to write automated test scripts, perform code reviews, and identify defects in software products before they are released to end-users.

Open Source Contributor

Many developers contribute to open-source projects written in C, such as operating systems (e.g., Linux, FreeBSD), libraries (e.g., OpenSSL, SQLite), and compilers (e.g., GCC). Contributing to open-source projects allows developers to collaborate with peers, gain visibility in the community, and enhance their coding skills.

Conclusion