Credit inquiry program, which tell about bank balance of customer and diiferent functions

/* Fig. 11.8: fig11_08.c
  Credit inquiry program */
#include <stdio.h>

/* function main begins program execution */
int main( void )
{
  int request;     /* request number */
  int account;     /* account number */
  double balance;  /* account balance */
  char name[ 30 ]; /* account name */
  FILE *cfPtr;     /* clients.dat file pointer */

  /* fopen opens the file; exits program if file cannot be opened */
  if ( ( cfPtr = fopen( "clients.dat", "r" ) ) == NULL ) {
     printf( "File could not be opened\n" );
  } /* end if */
  else {
   
     /* display request options */
     printf( "Enter request\n"
        " 1 - List accounts with zero balances\n"
        " 2 - List accounts with credit balances\n"
        " 3 - List accounts with debit balances\n"
        " 4 - End of run\n? " );
     scanf( "%d", &request );
     /* process user's request */
     while ( request != 4 ) {

        /* read account, name and balance from file */      
        fscanf( cfPtr, "%d%s%lf", &account, name, &balance );

        switch ( request ) {

           case 1:
              printf( "\nAccounts with zero balances:\n" );

              /* read file contents (until eof) */
              while ( !feof( cfPtr ) ) {

                 if ( balance == 0 ) {
                    printf( "%-10d%-13s%7.2f\n",
                       account, name, balance );
                 } /* end if */

                 /* read account, name and balance from file */
                 fscanf( cfPtr, "%d%s%lf",                    
                    &account, name, &balance );              
              } /* end while */

              break;
              printf( "\nAccounts with credit balances:\n" );

              /* read file contents (until eof) */
              while ( !feof( cfPtr ) ) {

                 if ( balance < 0 ) {
                    printf( "%-10d%-13s%7.2f\n",
                       account, name, balance );
                 } /* end if */

                 /* read account, name and balance from file */
                 fscanf( cfPtr, "%d%s%lf",                    
                    &account, name, &balance );              
              } /* end while */

              break;

           case 3:
              printf( "\nAccounts with debit balances:\n" );

              /* read file contents (until eof) */
              while ( !feof( cfPtr ) ) {

                 if ( balance > 0 ) {
                    printf( "%-10d%-13s%7.2f\n",
                       account, name, balance );
                 } /* end if */
                 /* read account, name and balance from file */
                 fscanf( cfPtr, "%d%s%lf",                    
                    &account, name, &balance );              
              } /* end while */

              break;          
         
        } /* end switch */

        rewind( cfPtr ); /* return cfPtr to beginning of file */

        printf( "\n? " );
        scanf( "%d", &request );
     } /* end while */

     printf( "End of run.\n" );
     fclose( cfPtr ); /* fclose closes the file */
  } /* end else */

  return 0; /* indicates successful termination */

 } /* end main */