C# Program: Convert user input to datetime with exception handling

C# Sharp Exception Handling: Exercise-9 with Solution

Write a C# program that creates a method that reads a date from the user in the format "dd/mm/yyyy" and converts it to a DateTime object. Handle an exception if the input format is invalid.

Sample Solution:

C# Sharp Code:

using System;

class Program {
  static void Main() {
    try {
      // Prompt the user to input a date in a specific format (dd/mm/yyyy)
      Console.Write("Input a date (format-> dd/mm/yyyy): ");
      string input = Console.ReadLine();

      // Convert the user-input string to a DateTime object using the ConvertToDate method
      DateTime date = ConvertToDate(input);

      // Display the formatted date to the user
      Console.WriteLine("Date: " + date.ToShortDateString());
    } catch (FormatException) {
      // Catch block for handling FormatException (invalid date format)
      Console.WriteLine("Error: Invalid date format. Please input a valid date in the format dd/mm/yyyy.");
    } catch (Exception ex) {
      // Catch block for handling other types of exceptions
      Console.WriteLine("An error occurred: " + ex.Message);
    }
  }

  // Method to convert a string to a DateTime object based on a specific format
  static DateTime ConvertToDate(string input) {
    // Define the date format expected from the user input
    string[] format = { "dd/MM/yyyy" };

    // Parse the input string to a DateTime object using the specified format
    return DateTime.ParseExact(input, format, null, System.Globalization.DateTimeStyles.None);
  }
}

Sample Output:

Input a date (format-> dd/mm/yyyy): 11/01/2019
Date: 11-01-2019

 
Input a date (format-> dd/mm/yyyy): 11/14/2019
Error: Invalid date format. Please input a valid date in the format dd/mm/yyyy.

  
Input a date (format-> dd/mm/yyyy): 00/00/2019
Error: Invalid date format. Please input a valid date in the format dd/mm/yyyy.

 
Input a date (format-> dd/mm/yyyy): 01-01-2019
Date: 01-01-2019

Explanation:

In the above exercise -

• The "Main()" method prompts the user to enter a date in the format "dd/mm/yyyy" using Console.Write() and Console.ReadLine(). The input is stored in the input variable.
• The program calls the ConvertToDate method, passing the input string as an argument.
• The ConvertToDate method uses DateTime.ParseExact to convert the string to a DateTime object, specifying the desired format "dd/MM/yyyy". If the input string cannot be parsed according to the specified format, a FormatException is thrown.
• In the "Main()" method, exceptions are handled using catch blocks. If a FormatException occurs, it means the input date format was invalid. The program catches this exception and displays an appropriate error message.
• Any other exceptions are caught by the generic catch block, and a general error message is displayed.
• The program displays the converted DateTime object using ToShortDateString() to format it as a short date string.

Flowchart:

C# Sharp Code Editor:

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