【c语言】注释转换（c注释变为c++注释）

输入输出函数知识链接

https://blog.csdn.net/weixin_41892460/article/details/82689266

头文件

#ifndef _COMMENT_CONVERT_H_
#define _COMMENT_CONVERT_H_



#include<stdio.h>
#include<stdlib.h>


enum  State
{
    NUL_STATE,//无注释状态
    C_STATE,//C注释状态
    CPP_STATE,//C++注释状态
    END_STATE//结束状态
};

void CommentConvert(FILE* pfIn, FILE *pfOut); //注释状态
void DoCState(FILE* pfIn, FILE *pfOut, enum State* ps);//C状态
void DoCppState(FILE* pfIn, FILE *pfOut, enum State* ps);//C++状态 
void DoNulState(FILE* pfIn, FILE *pfOut, enum State* ps);//结束




#endif

函数部分

#define _CRT_SECURE_NO_WARNINGS 1


#include "CommentConver.h"






void CommentConvert(FILE* pfIn, FILE *pfOut)
{

    enum State state = NUL_STATE;   
    while (state != END_STATE)
    {
        switch (state)
        {
        case NUL_STATE:
            DoNulState(pfIn, pfOut, &state);
            break;
        case C_STATE:
            DoCState(pfIn, pfOut, &state);
            break;
        case CPP_STATE:
            DoCppState(pfIn, pfOut, &state);
            break;
        default:
            break;
        }
    }
}




void DoCState(FILE* pfIn, FILE *pfOut, enum State* ps)
{
    int first = 0;
    int second = 0;
    int third = 0;
    first = fgetc(pfIn);
    switch (first)
    {
    case '*':
    {
                second = fgetc(pfIn);
                switch (second)
                {
                case '/'://进入C状态后如果读到*/就说明结束了C状态的注释  
                    third = fgetc(pfIn);//这里只是考虑避免注释到了正文  
                    if (third == '\n')
                    {
                        fputc(third, pfOut);
                    }
                    else
                    {
                        ungetc(third, pfIn);//读到非\0时就是*/后面有正文内容，所以回退一下  
                        fputc('\n', pfOut);
                    }
                    *ps = NUL_STATE;
                    break;
                case '*':
                    fputc(first, pfOut);
                    ungetc(second, pfIn);//遇到两个*，则第一个是正文的*  
                    break;
                default:
                    fputc(first, pfOut);
                    break;
                }
    }
        break;
    case '\n'://C注释换行问题  
        fputc(first, pfOut);
        fputc('/', pfOut);
        fputc('/', pfOut);
        break;
    case EOF:
        fputc(first, pfOut);
        *ps = END_STATE;
    default:
        fputc(first, pfOut);
        break;
    }
}
void DoCppState(FILE* pfIn, FILE *pfOut, enum State* ps)
{
    int first = 0;
    int second = 0;
    first = fgetc(pfIn);
    switch (first)
    {
    case '\n':
    {
                  fputc('\n', pfOut);
                  *ps = NUL_STATE;
    }
        break;
    case EOF:
        fputc(first, fputc('\n', pfOut));

        *ps = NUL_STATE;
        break;
    default:
        fputc(first, pfOut);
        break;
    }
}



void DoNulState(FILE* pfIn, FILE *pfOut, enum State* ps)
{
    int first = 0;
    int second = 0;
    int third = 0;
    first = fgetc(pfIn);
    switch (first)
    {
    case '/':
        second = fgetc(pfIn);
        switch (second)
        {
        case '*':
        {
                    fputc('/', pfOut);//当读到/*时相当于是C状态，状态改变为C状态  
                    fputc('/', pfOut);//然后把C注释的标志/*变为C++注释的标志//  
                    *ps = C_STATE;
        }
            break;
        case '/':
        {
                    fputc(first, pfOut);//遇到//相当于C++状态，不用转换直接把读到的标志写进去  
                    fputc(second, pfOut);
                    *ps = CPP_STATE;//状态变为C++状态  
        }
            break;
        default:
            fputc(first, pfOut);
            fputc(second, pfOut);
            break;
        }
        break;
    case EOF://遇到EOF直接把状态变为结束  
        fputc(first, pfOut);
        *ps = END_STATE;
        break;
    default:
        fputc(first, pfOut);//没有读到注释的标注就直接把读到的写进去  
        break;
    }
}

test.c

#define _CRT_SECURE_NO_WARNINGS 1


#include "CommentConver.h"



void test()
{
    FILE* pfIn = NULL;
    FILE* pfOut = NULL;
    pfIn = fopen("input.c","r");
    if (NULL == pfIn)
    {
        perror("open file for read");
        exit(EXIT_FAILURE);
    }
    pfOut = fopen("output.c", "w");
    if (NULL == pfOut)
    {
        perror("open file for  write");
        fclose(pfIn);
        exit(EXIT_FAILURE);
    }
    CommentConvert(pfIn, pfOut);
}




int  main()
{
    test();
    system("pause");
    return 0;
}