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Introduction to C

C is a general-purpose, procedural programming language developed by Dennis Ritchie in 1972. It is widely used for system programming, embedded systems, and developing operating systems. C is known for its efficiency and low-level memory manipulation capabilities.

Key Features of C:

• Procedural Language: C follows a step-by-step procedural approach.
• Portable: C programs can run on different platforms with minimal changes.
• Efficient: C provides direct access to memory and hardware.
• Rich Standard Library: C has a vast collection of built-in functions.
• Modularity: C supports modular programming using functions and libraries.
• Extensible: C allows integration with assembly language and other languages.

Why Learn C?

Learning C is essential for understanding the fundamentals of programming and computer science. It is the foundation for many modern programming languages like C++, Java, and Python. C is also widely used in:

• Operating Systems: Unix, Linux, and Windows are written in C.
• Embedded Systems: C is used in microcontrollers and IoT devices.
• Game Development: C is used in game engines and graphics programming.
• System Software: Compilers, interpreters, and device drivers are often written in C.

Basic Structure of a C Program

A C program typically consists of the following components:

// Preprocessor Directives
#include <stdio.h>

// Main Function
int main() {
    // Program Statements
    printf("Hello, World!\n");
    return 0; // Return Statement
}
      

• Preprocessor Directives: Include header files like stdio.h for input/output functions.
• Main Function: The main() function is the entry point of the program.
• Program Statements: These are the instructions executed by the program.
• Return Statement: The return 0; statement indicates successful program execution.

Example: Hello World in C

// C Hello World Program
#include <stdio.h>

int main() {
    printf("Hello, World!\n");
    return 0;
}
      

This program includes the standard input-output library (stdio.h) and uses the printf function to print "Hello, World!" to the console.

Compiling and Running a C Program

To compile and run a C program, follow these steps:

1. Write the program in a text editor and save it with a .c extension (e.g., hello.c).
2. Open a terminal or command prompt and navigate to the directory containing the program.
3. Compile the program using a C compiler like gcc:

   
   gcc hello.c -o hello
         

4. Run the compiled program:

   
   ./hello
         

Common C Libraries

C provides a rich set of standard libraries for various tasks. Some commonly used libraries include:

• stdio.h: Input/output functions like printf and scanf.
• stdlib.h: Memory allocation, random numbers, and other utility functions.
• math.h: Mathematical functions like sqrt, sin, and cos.
• string.h: String manipulation functions like strcpy and strlen.