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#include <stdio.h>
/* The C Programming Language: 2nd Edition
* Exercise 1-23:
* "Write a program to remove all comments from a C program. Don't forget to
* handle quoted strings and character constants properly. C comments do not
* nest."
*
* I'm not sure why the instructions tell the reader to account for quoted
* strings and character constants. Comments always begin with either // or
* /*, so that sets the boundary of state.
*
* The states for this program are IN_MULTI for a multi-line comment,
* IN_SINGLE for a single line comment, and OUT for being outside a comment.
* These three states are all I need to determine whether I should output the
* contents of the C file or not. Characters are only output when the state is
* OUT, and there are conditions for getting into and out of comment state.
*
* I don't know of any other way to do this without invoking some higher-level
* libraries.
*/
#define IN_MULTI 1
#define IN_SINGLE 2
#define OUT 0
char c, p;
int status;
int main() {
// Treat input like a stream, since that's all the K&R has explained so far.
while ((c = getchar()) != EOF) {
// Check for the ways to open a comment, and set state accordingly
if (c == '/' && status == OUT) {
// Look ahead and store the character that's returned
p = getchar();
if (p == '*') {
status = IN_MULTI;
} else if (p == '/') {
status = IN_SINGLE;
} else {
putchar(c);
putchar(p);
continue;
}
}
// Ignore everything in a single line comment until a newline
if (status == IN_SINGLE) {
if (c == '\n') {
putchar(c);
status = OUT;
continue;
}
}
// Ignore everything until you reach the end of a multi comment
if (status == IN_MULTI && c == '*') {
p = getchar();
if (p == '/') {
status = OUT;
continue;
}
}
// Output everything when we're not in a comment!
if (status == OUT) {
putchar(c);
}
}
/* derpsauce
*
*
* Testing comment for the lulz. lolololol
*/
}
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