C语到C++注释转换小项目

可将其分为下面四个状态进行讨论即可：

 #include<stdio.h>
 #include<windows.h>
 #define INPUTFILE  "input.c"
 #define OUTPUTFILE "output.c"     

 enum Status{
     NULLSTATUS,
     CPPSTATUS,
     CSTATUS,
     EOFSTATUS,
 };
 int  status = NULLSTATUS;

 void do_null_status(FILE *ifp,FILE *ofp){  //  初始态为普通状态 (没有参与注释部分的内容 )
     int c1=fgetc(ifp);
     switch(c1){
         case '/':{
             int c2 = getc(ifp);
             switch(c2){           //   .../*
                 case '*':
                     fputc('/',ofp);
                     fputc('/',ofp);
                     status = CSTATUS;
                     break;
                 case '/':         //     ... //
                     fputc('/',ofp);
                     fputc('/',ofp);
                     status = CPPSTATUS;
                     break;
                 case EOF:
                     fputc('/',ofp);
                     status = EOFSTATUS;
                     break;
                 default:         //     .../ ...
                     fputc('/',ofp);
                     fputc(c2,ofp);
                     break;
             }
             break;
         }
         case EOF:
             status = EOFSTATUS;
             break;
         default:
             fputc(c1,ofp);
             break;
     }
 }
 void do_cpp_status(FILE *ifp,FILE *ofp){     // 已进入C++风格注释（// ...)  保持此种风格注释
     int c = fgetc(ifp);
     switch (c) {
         case '\n' :            //   ....\n
             fputc('\n',ofp);
             status = NULLSTATUS;
            break;
         case EOF :
             status = EOFSTATUS;
            break;
         default:
            fputc(c, ofp);
           break;
     }
 }
 void do_c_status(FILE *ifp,FILE *ofp){    //  进入C风格注释 ( /* ...)  目的改为C++风格注释
     int c1= fgetc(ifp);
     switch(c1)
     {
         case '*':{
             int c2= fgetc(ifp);
             switch(c2){
                 case '/' :             //   //...*/...
                     fputc('\n' ,ofp);
                     status = NULLSTATUS;
                      break;
                  case EOF:
                      fputc('*' ,ofp);
                      status = EOFSTATUS;
                 default:
                     fputc('*',ofp);
                     ungetc(c2, ifp);      //这个地方调了好多遍才注意到，实在是愚钝。
                     break;
             }
             break;
         }
         case '\n':     //      /*  ... \n
             fputc('\n', ofp);
             fputc('/' , ofp);
             fputc('/' , ofp);
             break;
         case EOF:
             status= EOFSTATUS;
             break;
         default:       //   /* ...
             fputc(c1,ofp);
             break;
     }
 }
 void convert_work(FILE *ifp,FILE *ofp){
     while( status != EOFSTATUS){
         switch(status){
             case NULLSTATUS :
                 do_null_status(ifp,ofp);
                 break;
             case CPPSTATUS :
                 do_cpp_status(ifp,ofp);
                 break;
             case CSTATUS :
                 do_c_status(ifp,ofp);
                 break;
             case EOFSTATUS:
                 break;
             default:
                 break;
         }
     }
 }
 int main(){
     FILE *ifp=fopen(INPUTFILE,"r");
     FILE *ofp=fopen(OUTPUTFILE,"w");
     if(ifp == NULL || ofp == NULL){
         perror(" Open failed\n");
         exit();
     }
     convert_work(ifp , ofp);
     fclose(ifp);
     fclose(ofp);
     system("pause");
     return  ;
 } 

实例测试：