School of Engineering and Applied Science Department of Computer Science CSci 49 -- Introduction to C Computing http://www.seas.gwu.edu/~csci49/spring06 Prof. Michael B. Feldman mfeldman@gwu.edu

Project:

For example, if the user enters a starting date of May 10, 1999 and an ending date of September 15, 2002, the file will contain a line for each day from May 10 through December of 1999, all of 2000, all of 2001, and all dates in 2002 through September 15. Remember, when turning in your results,be sure to include these output files in their complete and unedited form. This may mean that there will be several pages to turn in.

Your dates should be output in the following format: May 3, 2002. When your program completes its run, test.datwill be an ordinary text file in your directory, which you can read with vi, type out (cat) to the screen, print, download, or whatever.

In this project you are NOT required to validate the dates or to test with invalid ones; you can assume the user will always enter valid data. However, your test plan must include several date ranges that will test whether your program "rolls over" properly from month to month and year to year. In the next project we'll combine this project with the Project 4 validation ideas.

Notes about Files

   1. /*------------------------------------------------------------
   2. | ShowFile.c
   3. | You can use this as a starting point for your projects.
   4. | Demonstrates the use of an output file.
   5. | Writes a 10 x 10 multiplication table to a file.
   6. | Author: Michael Feldman, The George Washington University
   7. | Last Modified: March 21, 2006
   8. ------------------------------------------------------------*/
   9. #include <stdio.h>
  10. int main()
  11. {
  12.   const int MAX = 10;
  13.   int row, column;        /* rows and columns of table */
  14.   FILE *myOutput;
  15.
  16.   /* The next statement associates the program variable myOutput
  17.      with a new output file that will be named multi.txt       */
  18.   myOutput = fopen ("multi.txt", "w");    /*
  19.
  20.   /* now write row x column products into file */
  21.   for (row = 1; row <= MAX; row++)
  22.   {
  23.      for (column = 1; column <= MAX; column++)
  24.      {
  25.         fprintf (myOutput, "%4d", row * column);
  26.      }
  27.      fprintf (myOutput, "\n");
  28.   }
  29.
  30.   /* Be sure to close the file at the end! */
  31.   fclose(myOutput);
  32.   printf ("Output file multi.txt has been created.\n");
  33.    
  34.   return 0;
  35. }

Here are the key things to notice and incorporate in your program:

1. line 14 declares a program variable that represents the file;
2. line 18 "opens" the file -- that is, actually creates the file multi.txt in your file system, makes it available for output (hence the "w"), and associates it with the program variable myOutput;
3. lines 25 and 27 write data into the file using fprintf, which works just like printf but puts the output into the file instead of on the screen;
   
4. line 31, which closes the file and is important to do just before your program ends.

What to submit:

Your grade will be calculated on a 20-point basis, as follows:

• 6 points -- analysis and design (including algorithm in structured English)
• 4 points -- test plan
• 6 points -- correct execution of program according to test plan
• 4 points -- layout and style of program source code

Extra credit:

MBF 3/21/06