Practice Assignment

Information

1. For this practice assignment you will write a function that strips out all of the comments in a C source file. Here's an example:

   This is the input file: input1.txt:

   /*************************************
      A simple header comment
   *************************************/
   int main(void) /* help */
   {
     /* a comment before   */
     /* in front */ int a = 8/4; /* at end */
     /* a comment after    */
   
     return a;
   }
   

   The file after running the program on it: output1.txt

   
   int main(void) 
   {
     
      int a = 8/4; 
     
   
     return a;
   }
   

   The border shows you that there is one blank line above the line containing main. There is also one blank line above the int a line and 2 blank lines below it.

   This is the prototype for the function:

   void stripcom(const char *filename);
   

   and this is the command line to compile it:

   gcc -O -Werror -Wall -Wextra -ansi -pedantic main.c stripcom.c -o stripcom
   

   Additional tests:
   • input2.txt and output2.txt
   • input3.txt and output3.txt
   • input4.txt and output4.txt

   Here is a simple driver file: (main.c, HTML Text) You must specify the filename on the command line like this:

   stripcom foo.c
   

• You only have to deal with C-style comments (i.e. /* */), but you need to handle both single-line and multi-line comments.
• You can assume that the longest line in a file is 200 characters.
• You need to handle comments within double-quotes. (It isn't a comment if it's in a string.)
• You don't need to handle nested double-quotes like this:

  printf("The word \"foo\" is in double-quotes");
  

  However, you might want to take up that challenge after you've submitted this practice.

• Open the file for input in text/translate mode (i.e. "rt") and write the output to stdout. It is probably easiest to read one character at a time (fgetc) and write one character at a time.

• You may want to look at the ungetc function. (You may need to "peek ahead" at the next character to see if the / should be printed or not.)
• New lines that are inside of comments should not be printed out. This is important with multi-line comments.

• If you can't open the file, you are to print out a message like this:

  Can't open filename
  

  with filename replaced by the actual file you were trying to open.
• Here's a hint on the algorithm used - Use pointers to walk through the text. This means that your pointer will be in one of two states: the pointer is pointing into a comment or the pointer is NOT pointing into a comment. If you are in a comment, you simply discard the character. If you are NOT in a comment, you print the character.