Fundamentals of C

C Programming

What is C?s

C is a general-purpose programming language created by Dennis Ritchie in 1972 at Bell Labs. It is fast, powerful, and forms the foundation of many modern languages. C is closely tied to the development of UNIX.

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Constants

Constants are fixed values that do not change during program execution. They can be Primary (integer, floating-point, character) or Secondary (string, array, pointer, enum, struct, macro).

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Variables

Variables are named memory locations used to store data. They can hold constants such as integers, characters, or floating-point numbers. Example:

int age = 25;

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Data Types

Data types define the type and size of data a variable can store. Examples: int (4 bytes), float (4 bytes), double (8 bytes), char (1 byte), void (no value).

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Operators

Operators are symbols that perform operations on variables and values. Main categories include:

• Arithmetic
• Assignment
• Comparison
• Logical

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Header File Libraries

Header files contain function declarations, macros, and definitions. They allow you to use built-in functions like printf() without writing them yourself. Example: <stdio.h> for input/output functions.

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Hello World Program

#include <stdio.h>

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