学习笔记1——C语言库函数在文本中指定地方添加和删除一段

    调用C语言库函数，在文本中添加和删除这段(红色标记)

    End Extended Reserved Data:

    [Reserved Data]

    0x4f505448

    0x00000002

    0x45524158

    0x0000000c

    0x00000000

    0x5465726D

    0x00000008

    End Reserved Data

    [Image List]

 

 测试代码

#include <stdio.h>
#include <string.h>
void main()
{
 int nCount,erase=0; //erase=0 删除这段，erase=1添加这段
 if (erase==0)
 {
   FILE *pFile= fopen ( "test.txt" , "r+" );
   if (pFile==NULL)
   {}
   fseek (pFile,0,SEEK_END);
   nCount = ftell (pFile); //算出文件长度
   fseek (pFile,0,SEEK_SET);
   char *pBuff = new char [nCount+1];
   char *pBuffTemp = new char [nCount+1];
   memset (pBuff,0,nCount+1);
   memset (pBuffTemp,0,nCount+1);
   char *pBuff1,*pBuff2;
   fread (pBuff,1,nCount,pFile);
   fclose (pFile);
   pBuff1= strstr (pBuff, "End Extended Reserved Data:" ) //指针定位
   pBuff2= strstr (pBuff, "[Image List" ); //指针定位
   strcpy (pBuffTemp,pBuff2);
   pBuff1 = pBuff1+28;
   pBuff1[0]=0;
   strcat (pBuff,pBuffTemp);
   nCount= strlen (pBuff)+1;
   FILE *pFile1 = fopen ( "test.txt" , "w+" ); //重新打开该文件，清空内容
   fwrite (pBuff,1,nCount,pFile1); //写入缓存中的数据
   fclose (pFile1);
 }
else
 if (erase == 1)
 {
   char StringBuff[]= "[Reserved Data]\n0x4f505448\n0x00000002\n0x45524153\n0x0000000c\n0x00000000\n0x5465726D\n0x00000008\nEnd Reserved Data\n" ;
   FILE *pFile= fopen ( "test.txt" , "r+" );
   if (pFile==NULL)
   {}
   fseek (pFile,0,SEEK_END);
   nCount= ftell (pFile);
   fseek (pFile,0,SEEK_SET);
   char *pBuff= new char [nCount+1];
   char *pBuffTemp = new char [nCount+1];
   memset (pBuff,0,nCount+1);
   memset (pBuffTemp,0,nCount+1);
   char *pBuff1,*pBuff2;
   fread (pBuff,1,nCount,pFile);
   fclose (pFile);
   pBuff1= strstr (pBuff, "End Extended Reserved Data:" );
   pBuff1=pBuff1+28;
   pBuff2= strstr (pBuff, "[Image List]" );
   strcpy (pBuffTemp,pBuff2);
   strcpy (pBuff1,StringBuff);
   pBuff1=pBuff1+ strlen (StringBuff)+1;
   pBuff[0]=0;
   strcat (pBuff,pBuffTemp);
   nCount= strlen (pBuff)+1;
   FILE *pFile1= fopen ( "test.txt" , "w+" );
   fwrite (pBuff,1,nCount,pFile1);
   fclose (pFile1);
 }
}