Simple Age Calculator App using Tkinter in Python

from tkinter import * from tkinter import messagebox as mb from datetime import date def different_date(): given_year_field.config(state = "normal") given_month_field.config(state = "normal") given_day_field.config(state = "normal") different_date_button.config(state = "disabled") current_date_button.config(state = "normal") def current_date(): given_year_field.config(state = "disabled") given_month_field.config(state = "disabled") given_day_field.config(state = "disabled") different_date_button.config(state = "normal") current_date_button.config(state = "disabled") given_year_var.set(current_year) given_month_var.set(current_month) given_day_var.set(current_day) def reset_entries(): birth_year_field.delete(0, END) birth_month_field.delete(0, END) birth_day_field.delete(0, END) given_year_field.config(state = "disabled") given_month_field.config(state = "disabled") given_day_field.config(state = "disabled") different_date_button.config(state = "normal") current_date_button.config(state = "disabled") given_year_var.set(current_year) given_month_var.set(current_month) given_day_var.set(current_day) age_var.set("") birth_year_field.focus_set() def reset(): reset_entries() mb.showinfo("Reset Entries", "All Entries are reset successfully!") def check_for_errors(): if (birth_year_field.get() == "" or birth_month_field.get() == "" or birth_day_field.get() == "" or given_year_field.get() == "" or given_month_field.get() == "" or given_day_field.get() == ""): mb.showerror("Input Error", "Invalid Format! Please Try Again.") reset_entries() return -1 def calculate_age(): val = check_for_errors() if val == -1: return else: birth_year = int(year_var.get()) birth_month = int(month_var.get()) birth_day = int(day_var.get()) given_year = int(given_year_var.get()) given_month = int(given_month_var.get()) given_day = int(given_day_var.get()) try: birth_date = date(birth_year, birth_month, birth_day) given_date = date(given_year, given_month, given_day) if (birth_date < given_date): days_left = given_date - birth_date age = int(abs((days_left.total_seconds()) / (365.242 * 24 * 3600))) age_var.set(str(age) + " Years Old") else: mb.showerror("Input Error", "The difference in date is big!") reset_entries() except ValueError: mb.showerror("Out of Range", "Entered Date is out of range.") reset_entries() if __name__ == "__main__": gui_root = Tk() gui_root.title("Age Calculator App") gui_root.geometry("600x450+650+250") gui_root.resizable(0, 0) header_frame = Frame(gui_root) entry_frame = Frame(gui_root) result_frame = Frame(gui_root) header_frame.pack(pady = 10) entry_frame.pack(pady = 10) result_frame.pack(pady = 10) header_label = Label( header_frame, text = "AGE CALCULATOR", font = ("verdana", "20", "bold"), fg = "Green" ) header_label.pack(fill = "both", pady = 10) year_label = Label( entry_frame, text = "Year", font = ("verdana", "10"), fg = "#000000" ) month_label = Label( entry_frame, text = "Month", font = ("verdana", "10"), fg = "#000000" ) day_label = Label( entry_frame, text = "Day", font = ("verdana", "10"), fg = "#000000" ) dob_label = Label( entry_frame, text = "Date of Birth:", font = ("verdana", "10", "bold"), fg = "#000000" ) given_date_label = Label( entry_frame, text = "Given Date:", font = ("verdana", "10", "bold"), fg = "#000000" ) year_label.grid(row = 0, column = 1, padx = 10, pady = 10) month_label.grid(row = 0, column = 2, padx = 10, pady = 10) day_label.grid(row = 0, column = 3, padx = 10, pady = 10) dob_label.grid(row = 1, column = 0, padx = 10, pady = 10, sticky = W) given_date_label.grid(row = 4, column = 0, padx = 10, pady = 10, sticky = W) current_year = date.today().year current_month = date.today().month current_day = date.today().day year_var = StringVar(entry_frame) month_var = StringVar(entry_frame) day_var = StringVar(entry_frame) given_year_var = StringVar(entry_frame) given_month_var = StringVar(entry_frame) given_day_var = StringVar(entry_frame) year_var.set("") month_var.set("") day_var.set("") given_year_var.set(current_year) given_month_var.set(current_month) given_day_var.set(current_day) birth_year_field = Entry( entry_frame, width = 6, font = ("verdana", "10"), textvariable = year_var, justify = CENTER, relief = GROOVE ) birth_month_field = Entry( entry_frame, width = 4, font = ("verdana", "10"), textvariable = month_var, justify = CENTER, relief = GROOVE ) birth_day_field = Entry( entry_frame, width = 4, font = ("verdana", "10"), textvariable = day_var, justify = CENTER, relief = GROOVE ) given_year_field = Entry( entry_frame, width = 6, font = ("verdana", "10"), textvariable = given_year_var, justify = CENTER, relief = GROOVE, state = "disabled" ) given_month_field = Entry( entry_frame, width = 4, font = ("verdana", "10"), textvariable = given_month_var, justify = CENTER, relief = GROOVE, state = "disabled" ) given_day_field = Entry( entry_frame, width = 4, font = ("verdana", "10"), textvariable = given_day_var, justify = CENTER, relief = GROOVE, state = "disabled" ) birth_year_field.grid(row = 1, column = 1, padx = 10, pady = 10) birth_month_field.grid(row = 1, column = 2, padx = 10, pady = 10) birth_day_field.grid(row = 1, column = 3, padx = 10, pady = 10) given_year_field.grid(row = 4, column = 1, padx = 10, pady = 10) given_month_field.grid(row = 4, column = 2, padx = 10, pady = 10) given_day_field.grid(row = 4, column = 3, padx = 10, pady = 10) different_date_button = Button( entry_frame, text = "Custom Date", width = 14, font = ("verdana", "10"), relief = GROOVE, command = different_date, bg = "purple", fg = "#ffffff", disabledforeground = "#907957" ) current_date_button = Button( entry_frame, text = "Use Current Date", width = 14, font = ("verdana", "10"),