Question

(Printing Dates in Various Formats) Dates are printed in several common formats. Two of the more common formats are 04/25/1955 and April 25, 1955 Write an application that reads a date in the first format and prints it in the second format.

Short answer

Convert "04/25/1955" to "April 25, 1955".

Step-by-step solution

Read Input Date

Read the input date given in the format MM/DD/YYYY, for example, "04/25/1955". This date format includes a two-digit month, a two-digit day, and a four-digit year, separated by forward slashes.

Split the Date String

Split the input date string using the '/' delimiter to separate the components of the date into month, day, and year. This will result in an array or list with three elements: month = "04", day = "25", and year = "1955".

Convert Month Number to Month Name

Create a mapping of month numbers to month names (e.g., "01" to "January", "02" to "February", etc.). Use this mapping to convert the two-digit month from the date into the corresponding month name. For the month "04", the month name is "April".

Construct the Output Format

Construct the new date string using the format: MonthName Day, Year. Use the month name obtained in the previous step, along with the day and year extracted from the original input. For the example input, the output string will be "April 25, 1955".

Print the Converted Date

Output the newly formatted date string to the user. For this example, print "April 25, 1955".

Key concepts

String Manipulation

In programming, string manipulation is essential for handling and processing text data effectively. When working with dates, especially in tasks like reformatting, knowing how to manipulate strings is crucial. Let's delve into some key operations:

• Splitting Strings: One common operation is splitting a string based on a specific delimiter. In the context of handling dates, the typical format might be "MM/DD/YYYY". By using the delimiter '/', we can easily separate this string into three core parts: month, day, and year.
• Concatenating Strings: After processing individual parts of a string, it's often necessary to concatenate them back together into a new format. Concatenation involves joining multiple strings into one. For instance, after converting the month number to a month name, you might concatenate it with the day and year to form a new string like "April 25, 1955".
• Substring Extraction: Sometimes, you may need to extract specific parts of a string. For example, if a date includes leading zeros, you might extract just the portion you need (like "04" for April), to maintain formatting precision.

Practicing these operations builds a solid foundation for handling a wide range of text data processing tasks in programming.

Mapping Month Numbers to Names

When reformatting dates, particularly in a programming task where you convert numerical month representations to their full names, mapping plays a crucial role. This might seem daunting, but it's quite straightforward.

• Understanding Mappings: Mapping is simply associating each month number with its corresponding name. For instance, "01" maps to "January," "02" to "February," and so on up to "12" for "December".
• Implementing Mappings: In many programming languages, this is often done using arrays or dictionaries. A simple array can be indexed where the index corresponds to the month number. Alternatively, a dictionary could hold pairs: key (month number) and value (month name).
• Practical Example: In Java, an array like `String[] months = {"", "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};` allows you to access the month name by numeric index. For instance, `months[4]` results in "April".

This mapping facilitates converting dates from numeric formats to more readable ones, enhancing user comprehension.

Input/Output in Java

Handling input and output (I/O) is fundamental in Java programming, particularly when working on applications that interactively engage with users by reading and formatting data. Let's explore I/O basics, focusing on formatting dates:

• Input Operations: Java offers several mechanisms for reading user input, with `Scanner` being one of the most common classes used. To read a date string, you might initialize a Scanner object to capture user input, facilitating the subsequent processing of the date format.
• Output Operations: Once processed, displaying results back to users is generally done using methods like `System.out.println()`. This prints the newly formatted date to the console, providing the user with clear, formatted output.
• String Formatting: Often, output needs formatting for better readability. Java provides various methods for string formatting, such as `String.format()` or using `System.out.printf()` for inline formatting. These methods enable precise control over how text is displayed, aiding in tasks like neatly presenting restructured date strings.

Having a solid grasp of Java I/O operations is invaluable, particularly when working with dynamic tasks such as date formatting, where clear, user-friendly output is crucial.