#include <stdio.h>
#include <stdlib.h>
/* Functions */
void check_comment (char) ; // checks for both types of comments, then passes on control to below comments
void block_comment () ; // handles block or multiline comments
void single_comment () ; // handles single line comments
/* 2 file pointers - 1st is for the file in which we check for comments,
and 2nd is the file in which we copy the code after removing comments */
FILE *fp , *fp2;
int main(void)
{
char c;
fp = fopen ("test.txt","r") ; // open the first file in read mode
fp2 = fopen ("mynewfile.txt","w") ; // open the second file in write mode
while((c=fgetc(fp))!=EOF) // read the file character by character
check_comment(c); // check for each character if it seems like the beginning of a comment
// close both the files at the end of the program
fclose(fp);
fclose(fp2);
return 0;
}
//handles both types of comments
void check_comment(char c)
{
char d;
if( c == '/') // if the character starts with '/', it 'could' be a comment
{
if((d=fgetc(fp))=='*') // if the next character we read is '*', it is the beginning of multiblock comment
block_comment(); // pass control to function that handles multiblock comments
else if( d == '/') // else if the next character we read is '/', it is the beginning of single line comment
{
single_comment();// pass control to function that handles single line comment
}
else
{
// if both the cases fail, it is not a comment, so we add the character as it is in the new file.
fputc(c,fp2);
fputc(d,fp2);
}
}
// again, if all above fails, we add the character as it is in the new file.
else
fputc(c,fp2);
}
// function that handles block comments
void block_comment()
{
char d,e;
while((d=fgetc(fp))!=EOF) // the block comment has started, read the character by character
{
/* keep reading the characters and do nothing,
as they do not have to be copied into the new file (we are removing the comments)
*/
if(d=='*') // if the comment 'seems' like ending
{
e=fgetc(fp); // check if it actually ends (block comments end with '*/')
if(e=='/') // if the comment 'has' ended, return from the function
return;
}
}
}
// function that handles single line comments
void single_comment()
{
char d,e;
while((d=fgetc(fp))!=EOF) // the single line comment has started, read the character by character
{
/* keep reading the characters and do nothing,
as they do not have to be copied into the new file (we are removing the comments)
*/
if(d=='\n') // check if the comment ends (single comments end with '\n', or newline)
return; // if the comment 'has' ended, return from the function
}
}
