- fopen, fclose, fwrite, fread, ftell, fseek, fprintf, fscanf, feof,
   fileno, fgets, fputs, fgetc, fputc.
 - FILE *fp for file pointer.
 - Modes like r, w, a

- fstream f
 - f.open, f.close,  f>>, f<<, f.seekg, f.seekp, f.tellg, f.tellp, f.read, f.write, f.eof.
 - Modes like ios::in, ios::out, ios::bin , etc...