Exercise 1.23 - Remove comments from a C program


Write a program to remove all comments from a C program. Don’t forget to handle quoted strings and character constants properly. C comments don’t nest.



If two subsequent characters start with / and *, we say we are in-comment, If we find two characters which are / and /, we will print the first character and start treating the second / as the possible start of comment. In the same manner, if we encouter a single quote or a double quote character, then we understand we are inside a quoted string, so we putchar everything before we find the matching character again. Within a quoted string, if we encouter a special character, then we try to read them literally as two characters and print them.

If / is followed by any other character, we simply print them.