c++读取list.txt中每行的字符串以及写入二进制文件

#include <fstream>

 #include <fstream>
 string path = "";
 FILE* fp = fopen(path.c_str(), "r");
 while(!feof(fp)){
   char str[];
   fgets(str, , fp);
   string str_s(str);
   int eindx = str_s.find("XX.jpg");
   string filename = "XX" + str_s.substr(, eindx) + ".jpg";
   im = imread(filename, CV_LOAD_IMAGE_COLOR);
   if(im.empty()){
      fprintf(stderr, "imread %s failed\n", filename);
      return -;
 }

 FILE *fd = NULL;
 string tmp = lines_[lines_id_].first;
 int eindx = tmp.find("XX.png");
 string finenames = "XXX" + tmp.substr(, eindx) + "y";
 if(fd){
     fwrite(dmap.data, sizeof(float), dmap.cols*dmap.rows, fd);
     fclose(fd);
 }else{
 LOG(INFO) << "CANNOT OPEN FILE " << "XXX" + tmp.substr(, eindx) + ".y";
 }