주석 삭제 프로그램

[문제]

(1) abcd/*1234*/efg
-> abcdefg

(2) abc/abcd/*1234*/efg
-> abc/abcdefg

(3) abc/*123*456*/def
-> abcdef

(4) abcd/*123*/ef/*45*/gh
-> abcdefgh

(5) abc/*/123*/def
-> abcdef

(6) abcd/*123/*ddd*/45*/ef
-> abcd45*/ef

(7) abcd//1234
-> abcd

(8) abcd//1234/*!!!*/567
-> abcd

(9) abcd/*123***/defg
-> abcddefg

(10) abcd/*123****/defg
-> abcddefg

 

////////////////////////////////////////////////////////////////////////////////////////

 

#define IN 1
#define OUT 0
#include <stdio.h>
#include <string.h>

void main()
{
    FILE *fp;
    char ch, ch2, ch3;
    int state = OUT;
   
    fp = fopen("output.txt", "w");
   
    printf("\t<< 주석 삭제 프로그램 (종료 : ctrl+z) >>\n\n");
   
    while((ch=getchar()) != EOF)
    {
        if(ch=='/')
        {
            if(ch3=='*') // 주석 종료 '*/'
                state = OUT;
            ch2 = getchar();
           
            if(ch2=='*') // 주석 시작 '/*'
                state = IN;
            else if( state == IN ) // 주석 내부
                continue;
            else if ( ch2=='/' ) // 주석 시작 '//'
            {
                state = IN;
                while(getchar() != '\n')
                    ; // '//'는 enter까지 주석처리
            }
            else // 주석X
            {
                if(ch3!='*')
                    fputc(ch, fp);
                fputc(ch2, fp);
            }
        }
        else if(ch=='*' && state==IN)
        {
            ch3 = getchar();
            if(ch3=='/') // 주석 종료 '*/'
                state = OUT;
        }
        else if(state==OUT) // 주석 외부
            fputc(ch, fp);
    }
    printf("\n=> output.txt에 저장 되었습니다\n");
}