Simple Interest Calculator Using Python

The code `import tkinter as tk` and `from tkinter import messagebox` brings in necessary elements from the `tkinter` package to construct graphical user interfaces in Python. The `tkinter` package is brought in with the nickname `tk` to simplify the utilization of its components and methods across the code. Furthermore, `messagebox` is imported directly from `tkinter` to allow for the generation of pop-up dialog boxes that can exhibit error messages or other notifications, offering a means to engage with users and manage exceptions or alerts within the GUI application.

def calculate_interest_by_Chirag():
    
    try:
        principal_amount = float(principal_entry.get())
        rate_of_interest = float(rate_entry.get())
        time_taken_for_amount = float(time_entry.get())
        SI = (principal_amount * rate_of_interest * time_taken_for_amount) / 100
        result_label.config(text=f"Simple Interest: {SI:.2f}")
    except ValueError:
        messagebox.showerror("Input Error", "Please enter valid numbers.")

The `calculate_interest_by_Chirag()` function is designed to compute the simple interest using user-provided inputs from the GUI. It acquires the principal amount, rate of interest, and time period from their corresponding entry fields, converts them into floating-point numbers, and then applies the formula  SI=(p*r*t)/100, to determine the simple interest. The resulting value is exhibited in the `result_label` with a precision of two decimal places. In case any of the inputs are deemed invalid (i.e., not numerical values), a `ValueError` is captured, and the user is prompted to input valid numerical values through an error message.

app = tk.Tk()
app.title("Simple Interest Calculator")

The program initializes an instance of the `Tk` class from the `tkinter` module, and assigns it to the variable `app` in order to create the main application window for the GUI. This window acts as the central interface for placing all graphical elements, including labels, buttons, and entry fields. The code `app.title(“Simple Interest Calculator”)` is used to set the window’s title to “Simple Interest Calculator,” which is displayed in the title bar to assist users in understanding the application’s purpose.

tk.Label(app, text="Enter principal amount:").pack(pady=5)

principal_entry = tk.Entry(app)
principal_entry.pack(pady=5)

tk.Label(app, text="Enter rate of interest (%):").pack(pady=5)

rate_entry = tk.Entry(app)
rate_entry.pack(pady=5)

tk.Label(app, text="Enter time period (years):").pack(pady=5)

time_entry = tk.Entry(app)
time_entry.pack(pady=5)

tk.Button(app, text="Calculate", command=calculate_interest_by_Chirag).pack(pady=5)

result_label = tk.Label(app, text="Simple Interest: ")
result_label.pack(pady=20)

app.mainloop()