Programming 1 — C Programming Examples

This repository collects short C programs that accompany the lectures of the Programming 1 course. Its organization is based on bonigarcia/c-programming: each lecture is a folder, divided into topics, and each .c file is a standalone, commented program.

See the course overview for what you will learn, the learning outcomes, and where C is used, lecture by lecture.

Compiling and running

Requirements: gcc and make (Linux, WSL, macOS, or GitHub Codespaces).

make          # compile all examples
make clean    # remove compiled files

# or compile a single file
gcc -Wall -g lecture01-intro/hello_world/hello.c -o hello
./hello

Folders with their own Makefile contain multi-file programs (for example lecture01-intro/header_files); run make run inside that folder.

Labs

The handouts for the 4 lab sessions (plus the Lab 0 preparation lab) are in labs/:

• Lab 0 — Environment setup, Linux commands, SSH, Git/GitHub
• Lab 1 — C fundamentals
• Lab 2 — Arrays, strings, and debugging
• Lab 3 — Pointers and dynamic memory
• Lab 4 — Structs, function pointers, and multi-file programs

The repo includes a .devcontainer/ configuration for opening it in GitHub Codespaces (with gcc, gdb, make, and valgrind preinstalled).

Contents

Lecture 1: Course introduction

Topic	Examples
The "hello, world" program	hello.c
Functions (definition, calling, reuse)	print_hello.c
Header files, multi-file compilation, compile/link	header_files/
Variables, while loops (temperature table)	fahr_celsius.c, fahr_celsius_float.c
Arithmetic operators	arithmetic.c
Increment/decrement operators i++, ++i	increment.c
Comments	comments.c
Exercises: add, factorial, Fibonacci (recursive and iterative)	add.c, factorial.c, fibonacci.c

Lecture 2: Basic elements

Topic	Examples
Sizes of data types	sizeof_types.c
Declaring variables, constants, hexadecimal numbers	declare_assign.c
Type casting, loss of precision	casting.c, cast_in_function.c
Relational and logical operators	relational_logical.c
if / else if / else	if_else.c
for, while, do-while	loops.c
The char type and the ASCII table	char_ascii.c
Exercises 1, 2: converting characters to numbers, atoi	convert.c, my_atoi.c

Lecture 3: Arrays and pointers

Topic	Examples
switch, break, continue	switch.c, break_continue.c
1D arrays, finding the max	array_1d.c
2D arrays, max along an axis	array_2d.c
Exercises: inner product, matrix multiplication, convolution	inner_product.c, matrix_multiplication.c, convolution.c
Inserting and deleting array elements	array_insert_delete.c
Declaring pointers, & and *	pointer_basic.c
Pointers to arrays, array names are constant	pointer_to_array.c
Moving pointers, the *(++p) vs. *(p++) quiz	pointer_arithmetic.c
Call by value and call by reference	call_by_value_reference.c
Array pointers with functions (max, reversing an array, returning an array)	array_functions.c, even_odd_bit.c
malloc, free, realloc, memory leaks	malloc_free.c, realloc.c, memory_leak.c
Variable scope (global, local, heap)	scope.c
Structs, pointers to structs, ->	fraction.c, struct_pointer.c
Linked lists (access, insert, delete, free)	linked_list.c
Binary search trees	binary_tree.c

Lecture 7: Review

Topic	Examples
VS Code configuration: building, debugging with gdb	vscode/
A program for practicing breakpoints	sample.c
Allocating a 2D array with int **	alloc_2d.c
Allocating an n-dimensional array recursively, returning void *	alloc_nd.c

Freeing linked lists and binary trees: see free_list in linked_list.c and free_tree in binary_tree.c.

Lecture 8: Function pointers

Topic	Examples
Multi-dimensional array indexing (struct MultiArray, data + shape)	multi_array.c
Strings: char[] vs. char *, the '\0' character	string_basics.c
strlen, strcmp, strcat, strcpy, strstr	string_functions.c
Implementing string functions yourself	my_string.c
Function pointers, arrays of function pointers	function_pointer.c
Function pointers as parameters (reduce, qsort)	reduce.c, qsort_compare.c
typedef	typedef.c
#define: constants and macros	define.c
#ifdef: Debug / Release, per operating system	debug_release.c, platform.c
Multiple files: prototypes and implementations, compile and link	multiple_files/
Calling functions from a dynamic library (dlopen/dlsym)	dynamic_library/

Things to try

# Debug and Release builds with #ifdef
gcc -DDEBUG lecture08-function-pointers/preprocessor/debug_release.c -o debug && ./debug
gcc lecture08-function-pointers/preprocessor/debug_release.c -o release && ./release

# Check for memory leaks
cd lecture03-array-pointer/dynamic_mem
gcc -g memory_leak.c -o memory_leak && valgrind --leak-check=full ./memory_leak

# Debug with gdb
gcc -g lecture07-review/multi_array/sample.c -o sample && gdb ./sample

Further reading

• Brian Kernighan, Dennis Ritchie — The C Programming Language
• Nick Parlante — Essential C
• Harvard CS50x and the cs50.dev environment
• bonigarcia/c-programming
• Practice: LeetCode (number and array topics)