A simple Rust command-line application for checking whether a given number is a prime number.

• Interactive CLI: Continuously prompts the user to enter a number and checks its primality.
• Handles invalid input gracefully.
• Allows users to exit the program at any time by typing exit.
• Efficient primality test implementation for 64-bit unsigned integers.

• Rust (version 1.60 or newer recommended)
• A terminal or command prompt

Clone the repository and build the project using Cargo:

git clone https://github.com/hrosicka/prime-number.git
cd prime-number
cargo build --release

Run the application with Cargo:

cargo run --release

You will be prompted to enter a number. The program will indicate whether the number is prime. Type exit to quit.

Enter a number (or 'exit' to quit): 17

The number 17 is a prime number.

Enter a number (or 'exit' to quit): 20

The number 20 is not a prime number.

Enter a number (or 'exit' to quit): exit
Program terminated.

The application uses an efficient algorithm to check whether a number is prime:

• Returns false for numbers less than 2.
• Returns true for 2.
• Eliminates even numbers greater than 2.
• Checks divisibility up to the square root of the input number, skipping even numbers.

Lovingly crafted by Hanka Robovska

This project is licensed under the MIT License.