分析思路：状态转换
将注释分为 常规状态（null），C语言状态（/*）， Cpp状态（//）
用三种状态的转换来分析复杂多样的注释情况；
Commentconvert.h
#ifndef __COMMENTCONVERT_H__ #define __COMMENTCONVERT_H__ #define _CRT_SECURE_NO_WARNINGS 1 #include <stdio.h> #include <stdlib.h> typedef enum STATE { NULL_STATE, C_STATE, CPP_STATE, END_STATE, }STATE; void DoConverWork(FILE *pfin, FILE *pfout); //转换工作函数 void DoNULLState(FILE *pfin, FILE *pfout, STATE *ps); //空状态处理 void DoCState(FILE *pfin, FILE *pfout, STATE *ps); //C状态处理 void DoCPPState(FILE *pfin, FILE *pfout, STATE *ps); //Cpp状态处理 #endif //__COMMENTCONVERT_H__Commentcovert.c #include "CommentConvert.h" void DoConverWork(FILE *pfin, FILE *pfout)//转换工作函数 { STATE state = NULL_STATE; while (state != END_STATE) { switch (state) { case NULL_STATE: DoNULLState(pfin, pfout, &state); break; case C_STATE: DoCState(pfin, pfout, &state); break; case CPP_STATE: DoCPPState(pfin, pfout, &state); break; } } } void DoNULLState(FILE *pfin, FILE *pfout, STATE *ps) { int first = 0; first = fgetc(pfin); switch (first) { case '/': { int second = 0; second = fgetc(pfin); switch (second) { case '*'://c状态 { fputc('/', pfout); fputc('/', pfout); *ps = C_STATE; //指向C处理 } break; case '/'://cpp状态 { fputc(first, pfout); fputc(second, pfout); *ps = CPP_STATE;//指向cpp处理 } break; default: break; } } break; case EOF: *ps = END_STATE; break; default: fputc(first, pfout); break; } } void DoCState(FILE *pfin, FILE *pfout, STATE *ps) //c状态 { int first = 0; first = fgetc(pfin); switch (first) { case '*': { int second = fgetc(pfin); switch (second) { case '/': fputc('\n', pfout); *ps = NULL_STATE; break; default: fputc(first, pfout); ungetc(second, pfin);//返回*之后的字符 以防出现**/ } } break; case '\n': { fputc('\n', pfout); fputc('/', pfout); fputc('/', pfout); } break; default: fputc(first, pfout); break; } } void DoCPPState(FILE *pfin, FILE *pfout, STATE *ps)//cpp状态 { int first = 0; first = fgetc(pfin); switch (first) { case '\n': fputc('\n', pfout); *ps = NULL_STATE; break; case EOF: *ps = END_STATE; break; default: fputc(first, pfout); } } test.c
#include "CommentConvert.h" #define IN_FILENAME "input.c" #define OUT_FILENAME "output.c" int main() { FILE * pfwrite = NULL; FILE * pfread = NULL; pfread = fopen(IN_FILENAME, "r"); if (pfread == NULL) { perror("open file for read"); exit(EXIT_FAILURE); } pfwrite = fopen(OUT_FILENAME, "w"); if (pfwrite == NULL) { perror("open file for write"); exit(EXIT_FAILURE); } DoConverWork(pfread, pfwrite); fclose(pfread); fclose(pfwrite); return 0; }
