text: ftell() prototype
  long ftell(FILE* stream);
  The
  ftell() function takes a file stream as its argument and returns the current value of the file position indicator for the given stream as a long int type.
  It is defined in <cstdio> header file.
  ftell() Parameters
  stream: The file stream whose current position is returned.
  ftell() Return value
  On success, the
  ftell() function returns the file position indicator. Otherwise, it returns -1L.
  Example: How ftell() function works
  #include <iostream> #include <cstdio> using namespace std; int main() { int pos; char c; FILE *fp; fp = fopen("file.txt", "r"); if (fp) { while ((c = getc(fp)) != EOF) { pos = ftell(fp); cout << "At position " << pos << ", character is " << c << endl; } } else { perror("Error reading file"); } fclose(fp); return 0; }
  When you run the program, the output will be:
  At position 1, character is P At position 2, character is r At position 3, character is o At position 4, character is g At position 5, character is r At position 6, character is a At position 7, character is m At position 8, character is i At position 9, character is z At position 10, character is . At position 11, character is c At position 12, character is o At position 13, character is m