linux c 判断文件存在，遍历文件，随机修改文件内容

 #include<stdio.h>
 #include<stdlib.h>
 #include<time.h>
 #include<assert.h>
 #include<string.h>
 #include<dirent.h>
 #include<unistd.h>
 #include<sys/types.h>
 #include<sys/stat.h>
 #include<time.h>
 
 #define PATH_LEN  512
 //#define MODIFICATION_LEN 10
 //#define MODIFICATION_TIMES 5
 char source_file_folder[]="t5";
 char dest_file_folder[]="dest_file";
 
 int modification(char src_file[],int MODIFICATION_TIMES,int MODIFICATION_LEN,char source_file_dir[],char dest_file_dir[])
 {
     FILE *src_fp,*dst_fp;
     char src_file_path[PATH_LEN];
     char dst_file_path[PATH_LEN];
     snprintf(src_file_path,PATH_LEN,"%s/%s",source_file_dir,src_file);
     snprintf(dst_file_path,PATH_LEN,"%s/%s",dest_file_dir,src_file);
     src_fp=fopen(src_file_path,"a+");
     assert(src_fp!=NULL);
     fseek(src_fp,,SEEK_END);
     int src_file_len=ftell(src_fp);
     assert(src_file_len!=-);
     rewind(src_fp);
     int *random_offset=(int *)calloc(MODIFICATION_TIMES,sizeof(int));
     assert(random_offset!=NULL);
     srand((unsigned)time(NULL));
     int i=;
     do
     {
         random_offset[i]=rand()%src_file_len;
     }while(random_offset[i++]<=src_file_len && i<MODIFICATION_TIMES);
     dst_fp=fopen(dst_file_path,"w+");
     assert(dst_fp!=NULL);
     char *buff=(char *)malloc(src_file_len*sizeof(char));
     assert(buff!=NULL);
     if(fread(buff,src_file_len,,src_fp)==)
         fwrite(buff,src_file_len,,dst_fp);
     //printf("src file : %s\n",buff);
     //free(buff);
     i=;
     char *center_buff;
     while(i<MODIFICATION_TIMES)
     {
         int right_offset=random_offset[i]+MODIFICATION_LEN;
         right_offset=right_offset>src_file_len?src_file_len:right_offset;
         int center_len=right_offset-random_offset[i];
         center_buff=(char *)calloc(center_len,sizeof(char));
         memset(center_buff,'',center_len);
         fseek(dst_fp,random_offset[i],SEEK_SET);
         fwrite(center_buff,center_len,,dst_fp);
         free(center_buff);
         ++i;
     }
     free(buff);
     fclose(src_fp);
     fclose(dst_fp);
     return ;
 
 }
 
 void listDir(char *path,int modification_times,int modification_len,char source_file_dir[],char dest_file_dir[])
 {
     DIR *pDir;
     struct dirent *ent;
     char childpath[PATH_LEN];
     pDir=opendir(path);
     memset(childpath,,sizeof(childpath));
     while((ent=readdir(pDir))!=NULL)
     {
         if(strcmp(ent->d_name,".")==||strcmp(ent->d_name,"..")==)
             continue;
         //    if(ent->d_type==8)
         snprintf(childpath,PATH_LEN,"%s/%s",path,ent->d_name);
         printf("%s\n",childpath);
         modification(ent->d_name,modification_times,modification_len,source_file_dir,dest_file_dir);
     }
     closedir(pDir);
 }
 int main(int argc,char *argv[])
 {
     char ch;
     char *source_file_dir=source_file_folder;
     char *dest_file_dir=dest_file_folder;
     int modification_len=,modification_times=;
     if(argc<)
     {
         printf("Usage:%s -t modification_times -l modification_len -s source_file_folder -d dest_file_folder\n",argv[]);
         return ;
     }
     while((ch=getopt(argc,argv,"t:l:s:d:"))!=-)
     {
         switch(ch)
         {
             case 't':
                 modification_times=atoi(optarg);
                 break;
             case 'l':
                 modification_len=atoi(optarg);
                 break;
             case 's':
                 source_file_dir=optarg;
                 break;
             case 'd':
                 dest_file_dir=optarg;
                 break;
             default:
                 printf("%s -t modification_times -l modification_len -s souce_file_folder -d dest_file_folder",argv[]);
                 exit();
         }
     }
 
     if(access(source_file_dir,)==-)
     {
         printf("%s is not exist\n",source_file_dir);
         return -;
     }
     if(access(dest_file_dir,)==-)
     {
         if(mkdir(dest_file_dir,))
         {
             perror("mkdir dest folder failed \n");                   return -;
         }
     }
     listDir(source_file_dir,modification_times,modification_len,source_file_dir,dest_file_dir);
     return ;
 }

Makefile

all:rand_file_modification
 
rand_file_modification : rand_file_modification.c
    gcc -g -Wall -o $@ $^
 
clean :
    rm rand_file_modification