The Monster Database

As an example, we'll create a small database of movie monsters. Here is the data we'll start out with, together with the type of each datum:

Deciding what your data is and how to represent it is an important part of software design. Taking extra time here and thinking about all the angles can save much grief later on.

Part 1: Building a Monster struct

We'll start by creating a C struct to hold our monster data:

1. Download the file monster_tplt.c to your lab directory.

2. Rename it:

   $ mv monster_tplt.c monster.c
   

   Here's what it looks like:

   #include <stdio.h>
   #include <string.h>
   
   
   /*
    * First, we #define sizes of every string (char array) attribute in
    * the database. This is its maximum length plus one (and its minimum
    * width for table printing purposes).
    */
   #define NAME_SIZE 15
   /* add additional *_SIZE #define's according to the table above */
   
   /*
    * This "struct" declares all information we want to maintain in the
    * "monster" database. All strings have the #define'd sizes given
    * above.
    */
   typedef struct {
       char name[NAME_SIZE];
       /*
        * Add additional elements according to the table above and using
        * the *_SIZE #define's (for the char arrays only).
        */
   } Monster;
   
   
   /*
    * Initialize an array of structs to form the database.
    */
   Monster monsters[] = {
       {
           /* We'll initialize the first structure by position. */
           "Count Dracula",
           "Dracula",
           1931,
           "wooden stake",
           "Van Helsing",
           7.6,
       },
       {
           /*
            * We'll initialize the second stucture by attribute name,
            * rearranging the order just to show we can do it.
            */
           .rating=8.0,
           .film="Frankenstein",
           .weakness="fire",
           .name="The Monster",
           .year=1931,
           .defeatedBy="villagers",
       },
       /* add some more favorites here, if you have time */
       /*
        * A name of zero length terminates this list.
        */
       {
           "",
       },
   };
   
   
   void monster_print(Monster monster)
   /* print a "monster" */
   {
       int colonIndent = 15; /* set this empirically so the ':'s line up */
   
       /*
        * The following shows a good way to print out attributes: one per
        * line with the attribute name appearing as "ragged left"
        * followed by a ':'.
        */
       printf("%*s: %s\n",   colonIndent, "Name", monster.name);
       /*
        * Add additional printf() calls similar to the one above. Be sure
        * to use the format that matches the attribute type.
        */
   }
   
   int main(void)
   {
       /*
        * for each `monster[i]` in the `monsters` array (as long as
        *  `monster[i].name[0] != 0`)
        *     print it using monster_print()
        *     print an extra newline to separate outputs
        */
       return 0;
   }
   
   

3. Follow the instructions in the comments to complete the Monster struct definition and .

4. Compile your code as usual:

   $ gcc -Wall monster.c -o monster.exe
   

5. When you run it, your result should look like this:

   $ ./monster
          Name: Count Dracula
          Film: Dracula
          Year: 1931
      Weakness: wooden stake
   Defeated By: Van Helsing
        Rating: 7.6
   
          Name: The Monster
          Film: Frankenstein
          Year: 1931
      Weakness: fire
   Defeated By: villagers
        Rating: 8.0
   

Part 2: Creating an HTML Table

A convenient way to display struct data is in a table, and the HTML format used by browsers is a very flexible way to do this. We'll use a template plus parts of your monster.c to create a new source file monster_html.c that will output the same data in HTML format:

1. Download the file monster_html_tplt.c to your lab directory.

2. Rename it:

   $ mv monster_html_tplt.c monster_html.c
   

   Here's what it looks like:

   #include <stdio.h>
   #include <string.h>
   
   /*
    * Copy the Monster structure definition here.
    */
   
   /*
    * Initialize an array of structs to form the database.
    */
   Monster monsters[] = {
       {
           /* We'll initialize the first structure by position. */
           "Count Dracula",
           "Dracula",
           1931,
           "wooden stake",
           "Van Helsing",
           7.6,
       },
       {
           /*
            * We'll initialize the second stucture by attribute name,
            * rearranging the order just to show we can do it.
            */
           .rating=8.0,
           .film="Frankenstein",
           .weakness="fire",
           .name="The Monster",
           .year=1931,
           .defeatedBy="villagers",
       },
       /* add some more favorites here, if you have time */
       /*
        * A name of zero length terminates this list.
        */
       {
           "",
       },
   };
   
   void monster_printHtmlTableHeader(void)
   /* print the header for an HTML table of monster */
   {
       printf("<tr>\n"); /* HTML table rows begin with this tag */
       /*
        * Here's how to print the first column, which is "Name":
        */
       printf("<th>Name</th>\n");
       /*
        * Insert additional printf()s for the other column names, in
        * order.
        */
       printf("</tr>\n"); /* HTML table rows end with this tag */
   }
   
   void monster_printHtmlTableRow(Monster monster)
   /* print the data in "monster" as an HTML row */
   {
       printf("<tr>\n"); /* HTML table rows begin with this tag */
       printf("<td>%s</td>\n",  monster.name);
       /*
        * Insert additional printf()s for the other attribute values, in
        * order. Be sure to choose the right format for printf(). The
        * `rating` should be printed with one decimal place.
        */
       printf("</tr>\n"); /* HTML table rows end with this tag */
   }
   
   int main(void)
   {
       /*
        * print "<table>" to begin the HTML table
        * print the HTML table header using monster_printHtmlTableHeader()
        * for each monster in the `monsters` array (as long as name[0] != '\0')
        *     print it as a row in the table using monster_printHtmlTableRow()
        * print "</table>" to end the HTML table
        */
       return 0;
   }
   
   

3. Follow the instructions in the comments to insert the code from monster.c and add additional code to output HTML.

4. Compile your code as usual:

   $ gcc -Wall monster_html.c -o monster_html.exe
   

5. When you run it, you should get this:

   $ ./monster_html
   <table>
   <tr>
   <th>Name</th>
   <th>Film</th>
   <th>Year</th>
   <th>Weakness</th>
   <th>Defeated By</th>
   <th>Rating</th>
   </tr>
   <tr>
   <td>Count Dracula</td>
   <td>Dracula</td>
   <td>1931</td>
   <td>wooden stake</td>
   <td>Van Helsing</td>
   <td>7.6</td>
   </tr>
   <tr>
   <td>The Monster</td>
   <td>Frankenstein</td>
   <td>1931</td>
   <td>fire</td>
   <td>villagers</td>
   <td>8.0</td>
   </tr>
   </table>
   

   which is pretty ugly, but do this:

   $ ./monster_html >table.html
   

   and then open table.html with your browser of choice. (Just clicking on it from the file browser should do this.)

   Much better!