Programming in C – Notes

Introduction to C

C is a general-purpose, procedural programming language developed by Dennis Ritchie at Bell Laboratories in 1972. It is designed for system programming and is widely used in operating systems, embedded systems, and application development.

• Developed in 1972 by Dennis Ritchie
• Based on BCPL and B languages
• ANSI C standardized in 1989 (C89/C90)
• Updated standards: C99 (1999), C11 (2011), C17 (2017)

Features of C

• Simple: Easy to learn and understand
• Portable: Code runs on different platforms with minimal changes
• Efficient: Fast execution speed
• Low-level Access: Direct memory manipulation
• Rich Library: Large collection of built-in functions
• Modular: Supports functions and code reusability
• Structured: Supports structured programming

Structure of a C Program

// Preprocessor directives
#include <stdio.h>
#define MAX 100

// Global declarations
int global_var = 10;

// Function prototypes
void function_name();

// Main function
int main() {
    // Local declarations
    int local_var = 20;
    
    // Executable statements
    printf("Hello, World!\n");
    
    return 0;  // Return statement
}

// Function definitions
void function_name() {
    // Function body
}

A C program typically consists of preprocessor directives, global declarations, function prototypes, the main function, and function definitions.