import json from datetime import datetime

FILE_NAME = "history.json"

Ensure file exists

def init_file(): try: with open(FILE_NAME, "x") as f: json.dump([], f) except FileExistsError: pass

Save operation to JSON

def save_history(operation, a, b, result): data = { "operation": operation, "a": a, "b": b, "result": result, "time": datetime.now().strftime("%Y-%m-%d %H:%M:%S") }

with open(FILE_NAME, "r") as f:
    history = json.load(f)

history.append(data)

with open(FILE_NAME, "w") as f:
    json.dump(history, f, indent=4)

Calculator operations

def calculate(operation, a, b): if operation == "+": result = a + b elif operation == "-": result = a - b elif operation == "*": result = a * b elif operation == "/": if b == 0: return {"error": "Division by zero"} result = a / b elif operation == "**": result = a ** b elif operation == "%": result = a % b else: return {"error": "Invalid operation"}

save_history(operation, a, b, result)

return {
    "operation": operation,
    "a": a,
    "b": b,
    "result": result
}

Get history

def get_history(): with open(FILE_NAME, "r") as f: return json.load(f)