ISBN Verification Code 7-118-01984-4 pay attention to the difference between '4' and 4, use the length of fgets (STR, length, FP) with caution, or fcanf (FP, "% s limit

# Include <stdio. h>
# Include <stdlib. h>

 Int Main ()
{
 Char Table [ 11 ] = "  0123456789x  " ;
 Char STR [ 13 ];
 Int I, j = 10 , Sum = 0 ;

File * FP1, * fp2;
 If (FP1 = fopen ( "  In.txt  " , "  R  " ) = NULL ){
Printf ( "  Cocould not open file! \ N  " );
Exit ( 1 );
}

Fscanf (FP1,"  % S  " , STR );
 //  Fgets (STR, 14, FP1); note that the length cannot be 13, because STR [13] is not '\ 0', it is better to use fscanf and fprintf.  
 Fclose (FP1 );

 For (I = 0 ; I < 11 ; I ++ ){
 If (STR [I]! = '  -  ' ){
Sum + = (STR [I]- '  0  ' ) * J --;
}
}

Sum % = 11 ;
Sum = 11 -Sum;

 If (Fp2 = fopen ( "  Out.txt  " , "  W " ) = NULL ){
Printf ( "  Cocould not open file! \ N  " );
Exit ( 1 );
}

 If (Table [Sum] = STR [ 12 ]) { //  Convert table 4 to '4' and then compare  
 Fprintf (fp2, "  % S " , "  Right  " );
Printf ( "  Right \ n  " );
} Else {
STR [ 12 ] = Table [Sum];
Fprintf (fp2, "  % S  " , STR );
Printf ("  % S \ n  " , STR );
}

Fclose (fp2 );

Getchar ();
 Return   0 ;
}