"I Built a Calculator in C (CLI & GTK GUI) — My Learning Journey"

#tutorial #beginners #programming #learning

🚀 I Built a Command-Line Calculator in C (v1 & v2) — Now I’m Working on a GTK GUI Version (v3)

👋 Hi! I’m Guntu Jothi Ganesh, a 18-year-old self-taught developer with a growing passion for system-level programming and open-source. I recently completed two versions of a command-line calculator using C, and now I'm building a GUI version using GTK+ 3 on Windows.

This post is a quick showcase of my progress, what I’ve learned, and what I’m working toward.

🛠️ What I Built

🔹 Version 1: Basic Calculator

Operates with +, -, *, /
Takes two inputs and an operator
Displays a result with simple output

🔹 Version 2: Improved CLI Calculator

🔁 Added a loop for continuous calculations
❌ Checks for divide-by-zero
🎯 Cleaner input/output formatting
🧹 Graceful exit

📂 GitHub: calculator_v2.c

🧩 Now Building: Version 3 - GUI Calculator with GTK

I’m currently working on a graphical calculator using GTK+ — built in C with a nice interface, buttons for input, and result display in a GUI window.

GTK Features in Progress:

🖱️ Buttons for digits and operations
🪟 GTK window with layout design
🧠 Future plan: scientific operations (log, sin, cos, etc.)
💡 Learning how to use GTK in MSYS2 on Windows

📂 GitHub (work-in-progress): gtk_calculator_v3

🔍 What I’ve Learned So Far

Using switch-case, input handling, and loops in C
How to avoid scanf pitfalls
Writing readable, maintainable C code
Compiling GTK projects with gcc and pkg-config
Publishing releases and managing GitHub repos

🎯 What’s Next?

Polish the GTK interface and layout
Add scientific calculator functions
Package it cleanly with README, screenshots, and instructions
Start contributing to beginner open-source C projects

📣 I'd Love Your Feedback!

If you’re a C dev, GTK user, or just exploring programming, I’d love to hear your thoughts and suggestions. Feel free to drop a comment or check out my GitHub!