Text Editor

A lightweight terminal-based text editor written in C++, inspired by the classic kilo editor. Built from scratch using raw terminal I/O with no external dependencies beyond the C++ standard library.

Features

• Raw terminal mode — direct, low-level keyboard and display control
• File open & save — open existing files from the command line and save with Ctrl-S
• Full cursor navigation — arrow keys, Home/End, Page Up/Page Down
• Text editing — insert characters, newlines (Enter), backspace, and delete
• Line operations — split lines on Enter, merge lines on Backspace at line start
• Horizontal & vertical scrolling — handles files wider and longer than the terminal
• Status bar — displays filename, line count, and unsaved-changes indicator
• Message bar — shows contextual messages and warnings (fades after 5 seconds)
• Unsaved-change protection — requires pressing Ctrl-Q three times to quit with unsaved changes
• Tab rendering — tabs are expanded to the nearest 8-space boundary

Requirements

• A POSIX-compatible system (Linux, macOS)
• A C++17-capable compiler (e.g. g++, clang++)

Building

g++ -std=c++17 -Wall -Wextra -o editor main.cpp

Usage

# Open the editor with no file (new file)
./editor

# Open an existing file
./editor <filename>

Keyboard Shortcuts

Key	Action
Ctrl-S	Save file
Ctrl-Q	Quit (press 3× with unsaved changes)
Arrow Keys	Move cursor
Home / End	Jump to start/end of line
Page Up / Page Down	Scroll one screen at a time
Backspace / Ctrl-H	Delete character to the left
Delete	Delete character to the right
Enter	Insert new line

Project Structure

The editor is organized into five classes, all in a single main.cpp file:

Class	Responsibility
Terminal	Raw mode, key reading, window size, screen output
AppendBuffer	Efficient string building for screen refresh
EditorRow	Single line of text and its rendered representation
TextBuffer	Collection of rows, file I/O, and edit operations
Editor	Top-level coordinator — cursor, scrolling, key handling, UI