122 lines
7.4 KiB
Markdown
122 lines
7.4 KiB
Markdown
# Homework 1 — Text Justification
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Before starting this homework, make sure you have read and understood the Academic Integrity Policy.
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This homework assignment is a programming exercise involving simple text manipulation to format input
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text into a framed column with a specified width. You will work with command line arguments, file input
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and output, and the C++ Standard Template Library string and vector classes. Please read the entire
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assignment before starting to program.
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Your program will read words from an input file and greedily pack the words one at a time onto each line,
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making sure not to exceed the specified width. Your program will support three different methods for dealing
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with any extra, unused space on each line. The first, **flush left**, simply positions each word as far to the left as
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possible, leaving a gap of spaces (if any) on the right. The second, **flush right**, does the opposite, pushing all
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the words to the right, and puts the extra spaces on the left. In the final mode, **full justify**, the extra spaces
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are distributed evenly between the words. If the number of extra spaces on the line do not divide evenly into
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those “between” slots, the slots on the left will be assigned more spaces that the slots on the right.
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Let’s look at a simple example. Here is a sample input file, named example.txt:
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*Here is an example of text justification.*
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And here’s the output produced for that input file for the three different justification modes, for the specified
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text width of 16:
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**flush left**
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```txt
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--------------------
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| Here is an |
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| example of text |
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| justification. |
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--------------------
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```
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**flush right**
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```txt
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--------------------
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| Here is an |
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| example of text |
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| justification. |
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--------------------
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```
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**full justify**
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```txt
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--------------------
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| Here is an |
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| example of text |
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| justification. |
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--------------------
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```
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First note that the output includes a simple ascii art line box drawn around the text, but those characters
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do not count towards the specified line width of the text. In other words, each line of final output is actually
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4 characters longer, in this example, 20 total characters. Notice that the same words appear on each line
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in all three cases. The only difference is where the “extra” spaces appear. The top line has 6 extra spaces
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(16 - # of characters in “Here is an” = 6). In full justify mode, these spaces are evenly divided into the 2
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slots between the 3 words. The second line has 1 extra space (16 - # of characters in “example of text”
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= 1). This extra space (still in full justify mode) is assigned to the leftmost of the two slots on the second line. Also note a typical
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convention for full justify formatting: The last line of a block of text formatted with full justify is not forced
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to stretch all the way to the right edge. No extra space is inserted between words on the last line – it should
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be flush left justified only.
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## File I/O
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You will read the words to format from an input text file. You should not make any assumptions about the
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formatting of this file, except that the words will be separated by at least one whitespace character. Remember
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that whitespace characters include spaces, tabs, and newlines. Any punctuation in the file (including periods,
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commas, apostrophes, etc.) should be treated as part of the word if it is not separated from the word by
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spaces. The basic iostream string input operator, >>, will work perfectly for this assignment. The output of
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your program will be written to a file, and should follow the specifications in this handout and match our
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examples. Reading and writing files in C++ is very similar to std::cin and std::cout. See examples of
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STL file streams on the course webpage [Programming Information](https://www.cs.rpi.edu/academics/courses/fall23/csci1200/programming_information.php).
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## Command Line Arguments
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Your program will expect 4 command line arguments. The first is the name of the input file. The second is
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the name of the output file. The third argument is an integer that specifies the width of the text column. The
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fourth argument will be a string (flush_left, flush_right, or full_justify) specifying which formatting
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mode should be used. Here are examples of valid command lines for your program:
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```console
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./justify.exe example.txt example_16_flush_left.txt 16 flush_left
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./justify.exe example.txt example_16_flush_right.txt 16 flush_right
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./justify.exe example.txt example_16_full_justify.txt 16 full_justify
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```
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You should implement very simple error checking to ensure that 4 arguments are provided and that the
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input and output file streams are successfully opened. You should also check that the values for the third
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and fourth arguments are valid. Your program should exit gracefully with a useful error message sent to
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std::cerr if there is a problem with the arguments.
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You must follow the specifications for the command line, input file, and output file exactly to ensure you
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receive full credit from the Submitty homework submission autograder. We have provided sample input &
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output files on the course website. Examples of using command line arguments can be found on the course
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webpage: [Programming Information](https://www.cs.rpi.edu/academics/courses/fall23/csci1200/programming_information.php).
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## Corner Cases
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So now you understand the core requirements for this assignment, but you may already have thought of a
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few problem cases. For example, how should the program full justify a line that contains just a single word?
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There are no available slots between words to use to insert the extra spaces. In this case your program
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should simply left justify the line. Another question you might ask is what to do if one of the words in the
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file is (by itself!) wider than the width of the column? In your initial coding and testing we recommend you
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assume that this will never happen. This solution will be worth nearly full credit. To receive full credit on
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the assignment your program should handle this case by splitting the word and inserting a hyphen. Note
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that we do not expect you to properly split the words between syllables, as that would require a database
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of English words and syllables. If you think of other corner cases as you work on the assignment, propose
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reasonable ways to handle those situations. If those solutions are overly complex or tricky, you do not need
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to tackle the implementation, but you should write up your thoughts in your README.txt for the grader
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to read.
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## Submission Details
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Use good coding style when you design and implement your program. Organize your program into functions:
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don’t put all the code in main! Be sure to read the [Homework Policies](https://www.cs.rpi.edu/academics/courses/fall23/csci1200/homework_policies.php) as you put the finishing touches on your solution. Be sure to make up new test cases to fully debug your program and don’t forget
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to comment your code! Use the provided template [README.txt](./README.txt) file for notes you want the grader to read.
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You must do this assignment on your own, as described in the [Collaboration Policy & Academic Integrity](https://www.cs.rpi.edu/academics/courses/fall23/csci1200/academic_integrity.php) page. If you did discuss the problem or error messages, etc. with anyone, please list their names in your
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README.txt file. Prepare and submit your assignment as instructed on the course webpage. Please ask a TA
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if you need help preparing your assignment for submission.
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**Due Date**: 09/07/2023, 23:59pm.
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