C

Introduction to C

What C is and where it's used, compiling and running a program, the structure of main, printf output, and comments.

Variables, Data Types & Constants

Declaring variables, the basic data types and their sizes, format specifiers, type conversion, and constants.

Operators & Booleans

Arithmetic, assignment, comparison, and logical operators; integer division and remainder; booleans with stdbool.h; and precedence.

Conditions: if, else & switch

Branching with if, else if, and else; nesting; the ternary operator; switch with break and default; and writing clear conditions.

Loops

while, do-while, and for loops; break and continue; nested loops; and avoiding infinite and off-by-one errors.

Arrays

Declaring and initializing arrays, indexing and bounds, looping over arrays, finding max/min/average, and two-dimensional arrays.

Strings

Strings as null-terminated char arrays, string literals, string.h functions, character functions, and safe string handling.

User Input & Math

Reading input with scanf and fgets, checking scanf's return value, mixing them safely, and the math.h library.

Memory Addresses & Pointers

Memory addresses, declaring and dereferencing pointers, passing by reference, pointers and arrays, pointer arithmetic, and NULL.

Functions & Recursion

Defining functions, parameters and return values, declarations (prototypes), scope, header files, and recursion.

Structs & Enums

Grouping data with structs, typedef, arrays of structs, structs and pointers (->), nested structs, and enums.

Dynamic Memory Management

Stack vs heap, malloc, calloc, realloc, and free, checking for NULL, memory leaks, and dangling pointers.

File Handling

Opening files with fopen and modes, writing with fprintf and fputs, reading with fgets and fscanf, closing, and checking for errors.

Errors, Debugging & Input Validation

Compile errors vs runtime errors, return codes and errno, validating input with strtol, debugging with gdb and sanitizers, and defensive habits.