I'm confused by the assignment directives, but I think they are getting at pointer dereferencing. ccPtr can point to any element in records. Once assigned to a record, you dereference elements using the -> operator.

Try something like this:

Code:
#include <stdio.h>

struct creditcard  {
  int cc_number;
  int auth_number;
  double amt_charge;
};

int main(void) { 

  // Local Variables
  struct creditcard records[50];
  struct creditcard *ccPtr;

  // Begin
  records[25].cc_number = 4111111;
  records[25].auth_number = 56222;
  records[25].amt_charge = 29.95;

  ccPtr = &records[0];  //ccPtr now points to record[0]


  ccPtr->cc_number = 599121;
  ccPtr->auth_number = 89333;
  ccPtr->amt_charge = 49.95;

  printf("Credit Card Number:%d\nAuthorization Number:%d\nAmount To Charge:%.2f\n",
    ccPtr->cc_number,
    ccPtr->auth_number,
    ccPtr->amt_charge);


  ccPtr = &records[25];  //ccPtr now points to record[25]

  printf("Credit Card Number:%d\nAuthorization Number:%d\nAmount To Charge:%.2f\n",
    ccPtr->cc_number,
    ccPtr->auth_number,
    ccPtr->amt_charge);

  return 0;

} // end function main