How to Verify a Date and Display the Following Day Using Python

Submitted by razormist on Wednesday, August 6, 2025 - 22:59.

In this tutorial, we will learn how to program "How to Verify a Date and Display the Following Day Using Python."The objective is to correctly verify the inputted date and display the next day. This tutorial will guide you step by step through the entire process of validating the date format and calculating the following day. By the end of this tutorial, you will have a solid understanding of how to implement this task in Python—helping you strengthen your problem-solving abilities and enhance your coding skills.

This topic is straightforward to understand. Just follow the instructions provided, and you will be able to complete it with ease. The program will guide you step by step through the process of verifying date format. So, let’s dive into the coding process!

Getting Started:

First you will have to download & install the Python IDLE's, here's the link for the Integrated Development And Learning Environment for Python https://www.python.org/downloads/.

Creating Main Function

This is the main function of the application. The following code will display a simple GUI in terminal console that will display program. To do this, simply copy and paste these blocks of code into the IDLE text editor.

while True:
    print("\n=============== Verify a Date and Display the Following Day ===============\n")
 
    date = input("Enter the date (dd/mm/yyyy): ")
 
    try:
        dd, mm, yy = map(int, date.split('/'))
 
        # Check valid month
        if mm < 1 or mm > 12:
            print("Date is invalid: Invalid month.")
            continue
 
        # Determine max days in the month
        if mm in [1, 3, 5, 7, 8, 10, 12]:
            max_day = 31
        elif mm in [4, 6, 9, 11]:
            max_day = 30
        elif (yy % 4 == 0 and yy % 100 != 0) or (yy % 400 == 0):
            max_day = 29  # Leap year February
        else:
            max_day = 28  # Non-leap year February
 
        # Check valid day
        if dd < 1 or dd > max_day:
            print("Date is invalid: Invalid day for the given month/year.")
            continue
 
        # Compute next day
        if dd == max_day:
            dd = 1
            if mm == 12:
                mm = 1
                yy += 1
            else:
                mm += 1
        else:
            dd += 1
 
        print(f"The incremented date is: {dd:02d}/{mm:02d}/{yy}")
 
    except ValueError:
        print("Invalid input format. Please enter the date as dd/mm/yyyy.")
        continue
 
    opt = input("\nDo you want to try again? (yes/no): ").strip().lower()
    if opt == 'no':
        print("Exiting program....")
        break
    elif opt != 'yes':
        print("Invalid input. Exiting program....")
        break

This Python program verifies the validity of a user-inputted date in the format `dd/mm/yyyy` and then displays the next day if the input is valid. It checks for proper day and month ranges, accounts for leap years, and calculates the following day accordingly—handling month and year rollovers. The program runs in a loop, allowing the user to try again or exit based on input.

Output:

There you have it we successfully created How to Verify a Date and Display the Following Day Using Python. I hope that this simple tutorial help you to what you are looking for. For more updates and tutorials just kindly visit this site. Enjoy Coding!

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