Overview

This repo includes a set of examples for beginners to learn C. Each folder can be considered as separate project, that is, it has its own main() function. Hence, C files within a folder (and those in its sub-folders) have to be compiled and linked together.

These C concepts can be studied in the following programs:

• Pass by reference: average, noduplicates, reverse, swap
• enum: bmp2ascii, euler19, maze
• struct: bmp2ascii, distance, maze, rgb
• File IO: bmp2ascii, euler13, maze
• Arguments to main(): bmp2ascii, maze, temperature, timediff
• Function return: average, distance, maxstr
• sscanf: rgb, timediff
• sprintf: euler40
• for loops and printf: shapes
• Treating large numbers as strings: euler13
• Data handling: students

bmp2ascii is an example of how to deal with images, saving them in memory as an array of pixel data. This program is also an introduction to BMP file format and ASCII art.

bsearch illustrates the difference between linear and binary search. It also shows how to use a pointer to a function.

maze shows how to organize a program into multiple C header and source files. It also shows the use of documentation comments, which can help is correctly using and maintaining user-written functions.

mcpi introduces Monte Carlo simulation and how to make use of randomness.

snake is an example of a user-interactive game that can be played on a Windows terminal. It also illustrates the use of emojis, multi-byte symbols and UTF-8 encoding.

More Exercises

Here are some exercises that a student can attempt (not in any particular order):

• Conway's Game of Life
• Random Walk
• Vigenère cipher
• Any card game
• Sudoku solver
• Tetris
• Huffman coding
• Markdown to HTML converter
• C code formatter
• Basic calculator
• Web API call
• Replay a game of chess
• Balance an AVL tree
• Implement FIFO (queue) and LIFO (stack) using linked lists

Project Euler

In this repo, we solve some problems from Project Euler. For reference, answers are available at https://github.com/lucky-bai/projecteuler-solutions/blob/master/Solutions.md

Quizzes

1. Set 1: https://gist.github.com/arvindpdmn/50ee9e084806aa518f80efb9edf3f9fe
2. Set 2: https://gist.github.com/arvindpdmn/81a597bada7ad152f2d7ebb2ec3e6223

C Concepts

These are some essentials concepts that a beginner has to learn.

• Data types
  • char, short, int, long long, float, double
  • unsigned char, unsigned short, unsigned int, unsigned long long
• Size and range of values of each data type
• Number systems: binary, decimal, hexadecimal
• ASCII encoding: https://www.ascii-code.com/
• Comments: single line and multi-line
• Constants and variables
• Initialization of variables
• Arrays and their initialization
• Declaration versus definition
• Operators
  • arithmetic: + - * / % ++ --
  • comparison: == != >= <= > <
  • logical: && || !
  • bitwise: & | ^ ~ << >>
  • assignment: = += -= *= /= %= &= |= ^= <<= >>=
  • ternary: (? :)
  • pointers: & *
  • struct: . ->
  • operator precedence
• Scope: local, global, static
• Preprocessor directives: includes, macros, conditionals
• Naming conventions: variables, functions
• Branching: if, else if, else
• Loops
  • for, do-while, while
  • break, continue
• Basic programming pitfalls
  • Using a variable without initializing it
  • Copying or writing data beyond array boundary
  • Ignoring or overwriting the string-terminating '\0' character
  • Ignoring the signed or unsigned nature of the data type
  • Not freeing heap memory
  • Passing by value instead of by reference
  • Unreadable code due to:
    • lack of functions
    • improper indentation or spacing
    • unclear variable names
• Basic C library functions: https://en.cppreference.com/c
  • input/output: printf, scanf, sprintf, sscanf
  • string: strlen, strcpy, strncpy, strcmp, strncmp, strcat, strncat, strchr, strstr
  • file: fopen, fprintf, fscanf, fwrite, fclose
  • memory: malloc, free, calloc, memcpy, memcmp, memset
  • math: cos, sin, exp, log, log10, pow, sqrt

Books

1. The C Programming Language" (2nd Edition) by Brian W. Kernighan and Dennis M. Ritchie. Old book but a classic: https://www.amazon.in/Programming-Language-Ansi-Version-Old/dp/8120305965/ or https://www.cs.sfu.ca/~ashriram/Courses/CS295/assets/books/C_Book_2nd.pdf
2. C Programming: A Modern Approach" (2nd Edition) by K. N. King. An excellent beginner level book: https://github.com/Embed-Threads/Learn-C/blob/main/books/c-programming-a-modern-approach-2nbsped-0393979504-9780393979503_compress.pdf

Technical Papers to Read

1. https://www.cs.tufts.edu/cs/40/docs/CTrapsAndPitfalls.pdf

Installing C Environment in Windows + VS Code

1. Install VS Code: https://code.visualstudio.com/download

2. Install MSYS2: https://www.msys2.org/ or https://github.com/msys2/msys2-installer

• Open CMD
• Run .\msys2-x86_64-latest.exe in --confirm-command --accept-messages --root C:/msys64
• Add to PATH ENV variable: C:\msys64
• Open MSYS2 CRT64
• Run pacman -S base-devel mingw-w64-ucrt-x86_64-toolchain

3. Testing

• Open VS Code, open a Terminal
• Run gcc --version
• Run gdb --version