Overview

In this assignment you will write a program that searches for occurrences of given word within a given file. The word and the file name will be entered as command-line arguments.

Goals

The goals of this assignment are to give you experience:

• with console and file I/O,
• using the string library and C++ strings,
• using the cstring library and C-style strings, and
• using command-line arguments.

Specifications

The findWord program

All your code for this assignment should be placed in a file named findWord.cpp. Your findWord program will do the following:

• Read in a word and the name of a file from the command line. For our purposes a word is any sequence of non-whitespace characters.
• If the file does not exist or cannot be opened, an error message should be given and the program should stop.
• Otherwise the program should seach the file, line by line, for occurrences of the given word. An occurrence is any time the exact sequence of characters in the word appears. For example, there is one occurence of "the" in "therefore" and no occurrences of "the" in "with everyone". Capitalization also matters, i.e., "the" does not occur in "The quick brown fox".
• For each line in which the given word occurs, the program should print out the entire line preceded by the line number (see the example below).
• After processing the entire file, the program should report the total number of occurrences of the given word within the file.

You will need to use the iostream, fstream, string, and cstring libraries.

Hints and Suggestions

• The file echoArgs.cpp gives a very simple example of how to write a program that uses command line arguments. The file can also be found at:

  ~cs368-1/public/html/assignments/p5/files/echoArgs.cpp

• You can read in one entire line from a file using the getline method.  The file I/O example from class gives an example of how to use both the member function and the free function forms of the getline method.
• You may find the following particularly useful:From string:
  • c_str()
  • length()
  • substr(start_pos, num_chars)
  From cstring:
  • strcmp(str1, str2)

Example

An example of how your findWord program should run and the output it should produce is given below. The example uses the file test.txt which contains the following:

The attitude that programmers should not have to pay for features
that they do not use permeates the [C++] language.  Another example
will further illustrate this influence.  Imagine that an integer
variable holding a negative number is right-shifted by one location.
What bit value should be moved into the topmost position?  If we
look at the machine level, architectural designers are divided on
this issue.  On some machines, a right shift will move a zero into
the most significant bit position, while on other machines the sign
bit (which, in the case of a negative number, will be 1) is extended.
Either case can be simulated by the other, using software, by means
of a combination of tests and masks.

-- p. 4, "C++ for Java Programmers", Timothy Budd (Addison-Wesley, 1999)

The file test.txt can be found at:

~cs368-1/public/html/assignments/p5/files/test.txt

The following shows the compilation of the program as well as several runs. The user input at the command prompt is given in bold.

% g++ -g findWord.cpp -o findWord
% findWord
Proper usage: findWord <word> <file>
where
  <word> is a sequence of non-whitespace characters
  <file> is the file in which to search for the word
example: findWord the test.txt
% findWord the test.txt
Searching for 'the' in file 'test.txt'
2 : that they do not use permeates the [C++] language.  Another example
3 : will further illustrate this influence.  Imagine that an integer
5 : What bit value should be moved into the topmost position?  If we
6 : look at the machine level, architectural designers are divided on
8 : the most significant bit position, while on other machines the sign
9 : bit (which, in the case of a negative number, will be 1) is extended.
10 : Either case can be simulated by the other, using software, by means
# occurrences of 'the' = 13
% findWord C++ test.txt
Searching for 'C++' in file 'test.txt'
2 : that they do not use permeates the [C++] language.  Another example
13 : -- p. 4, "C++ for Java Programmers", Timothy Budd (Addison-Wesley, 1999)
# occurrences of 'C++' = 2
% findWord summer test.txt
Searching for 'summer' in file 'test.txt'
# occurrences of 'summer' = 0
% findWord the noFile.txt
File 'noFile.txt' could not be opened

Submitting Your Work

Make sure your code follows the style and commenting standards used in CS 302 and CS 367. Note: the commenting standards use javadoc comments for class, method, and constructor headers. You do not need to use javadoc comments in your c++ programs for CS 368; however, your comments should include the same information as the javadoc comments. For example, your function header comments should include a description of what the function does, the name and a short description of each parameter, and a description of the return value.

Electronically submit the following file to your in "handin" directory by the due date and time (or refer to the late policy):

• findWord.cpp containing your main function and file processing code. All your code for this program must be in this one file.
• If you are working with a partner, only one partner submits the program files, but both partners must submit to his/her own hand-in directory a completed README.txt file. Students working in pairs must follow the rules for pair programming.

Please turn in only the files named above. Extra files clutter up the "handin" directories.