Build a command-line calculator

Creating a command-line calculator in Python is straightforward and can be done with a simple script. Below is a basic example that supports addition, subtraction, multiplication, and division. It continuously prompts the user for input until they type “exit”.

python
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def calculator():
    print("Simple Command-Line Calculator")
    print("Type 'exit' to quit")

    while True:
        expression = input("Enter calculation (e.g. 2 + 3): ")
        if expression.lower() == "exit":
            print("Goodbye!")
            break

        try:
            # Evaluate the expression safely
            result = eval(expression, {"__builtins__": None}, {})
            print("Result:", result)
        except Exception as e:
            print("Error:", e)

if __name__ == "__main__":
    calculator()

How it works:

• The user inputs a math expression like 5 + 7 or 12 / 4.

• The script uses Python’s eval() with restricted built-ins for safety.

• Errors (like syntax or division by zero) are caught and displayed.

• Type exit to quit the program.

Would you like me to create a more advanced version with support for functions or a GUI?