下列程序的功能是（）。  
#include   main( ) 
 { FILE *fp1,*fp2;
   fp1=fopen(“d1.dat”,“r”); 
fp2=fopen(“d2.dat”,“w”);
   while(!feof(fp1))
    fputc(fgetc(fp1),fp2));
   fclose(fp1);
   fclose(fp2);  
}