04-simple-programs

Simple Programs

This module turns the earlier language concepts into small command-line programs. The examples focus on input parsing, text processing, file I/O, algorithms, and recoverable errors.

Contents

Topic or project	Main idea	How to run
cli_arguments	Read and validate command-line arguments	Compile the files in examples/ with rustc
file_io_basics	Read and write files with std::fs	Compile the files in examples/ with rustc
simple_algorithms	Implement searching and sorting directly	Compile the files in examples/ with rustc
text_processing	Transform and inspect strings	Compile the files in examples/ with rustc
calculator	Parse operands and dispatch operations	cargo run -p calculator
rfind	Search text from the command line	cargo run -p rfind -- --help
todo_app	Persist simple task data	cargo run -p todo_app
exercises	Repair and extend small programs	Follow each exercise README

The Cargo commands above should be run from this directory.

Validate the module

cargo fmt --all -- --check
cargo clippy --workspace --all-targets -- -D warnings
cargo test --workspace

The standalone examples are also checked by the repository's validation script. Generated Cargo artifacts are written to target/ and can be removed with cargo clean.

Suggested order

Start with command-line arguments and text processing, then work through file I/O and algorithms. Use the calculator before the todo application; the todo application combines parsing, collections, file persistence, and error handling.