int fseek ( FILE * stream, long int offset, int origin );

#include <stdio.h>

int main ()
{
      FILE * pFile;
      long size;

      pFile = fopen ("file.cpp","rb");
      if (pFile==NULL)
            perror ("Error opening file");
      else
      {
            fseek (pFile, 0, SEEK_END);   ///將文件指針移動文件結(jié)尾
            size=ftell (pFile); ///求出當前文件指針距離文件開始的字節(jié)數(shù)
            fclose (pFile);
            printf ("Size of file.cpp: %ld bytes.\n",size);
      }
      return 0;
}