Sample Interactive Session 1 (no deletes)

% cat licences
UBT878 1
KGB209 1
TEA311 3
MUK772 1
XYZ333 2
% cc -o hash hash.c license.c
% hash
  0:    NULL
  1:    NULL
  2:    NULL
  3: license: UBT878, num: 1, hash(license):  3
  4: license: KGB209, num: 1, hash(license):  4
  5: license: TEA311, num: 3, hash(license):  4
  6: license: MUK772, num: 1, hash(license):  5
  7: license: XYZ333, num: 2, hash(license):  3
  8:    NULL
  9:    NULL
 10:    NULL
 11:    NULL
 12:    NULL
Enter license number ---> FTK123
The 1st time for license: FTK123
  0:    NULL
  1:    NULL
  2:    NULL
  3: license: UBT878, num: 1, hash(license):  3
  4: license: KGB209, num: 1, hash(license):  4
  5: license: TEA311, num: 3, hash(license):  4
  6: license: MUK772, num: 1, hash(license):  5
  7: license: XYZ333, num: 2, hash(license):  3
  8:    NULL
  9:    NULL
 10: license: FTK123, num: 1, hash(license): 10
 11:    NULL
 12:    NULL
Enter license number ---> XYZ333
The 3rd time for license: XYZ333
  0:    NULL
  1:    NULL
  2:    NULL
  3: license: UBT878, num: 1, hash(license):  3
  4: license: KGB209, num: 1, hash(license):  4
  5: license: TEA311, num: 3, hash(license):  4
  6: license: MUK772, num: 1, hash(license):  5
  7: license: XYZ333, num: 3, hash(license):  3
  8:    NULL
  9:    NULL
 10: license: FTK123, num: 1, hash(license): 10
 11:    NULL
 12:    NULL
Enter license number ---> SSR474
The 1st time for license: SSR474
  0:    NULL
  1: license: SSR474, num: 1, hash(license):  1
  2:    NULL
  3: license: UBT878, num: 1, hash(license):  3
  4: license: KGB209, num: 1, hash(license):  4
  5: license: TEA311, num: 3, hash(license):  4
  6: license: MUK772, num: 1, hash(license):  5
  7: license: XYZ333, num: 3, hash(license):  3
  8:    NULL
  9:    NULL
 10: license: FTK123, num: 1, hash(license): 10
 11:    NULL
 12:    NULL
Enter license number ---> ULL585
The 1st time for license: ULL585
  0:    NULL
  1: license: SSR474, num: 1, hash(license):  1
  2: license: ULL585, num: 1, hash(license):  2
  3: license: UBT878, num: 1, hash(license):  3
  4: license: KGB209, num: 1, hash(license):  4
  5: license: TEA311, num: 3, hash(license):  4
  6: license: MUK772, num: 1, hash(license):  5
  7: license: XYZ333, num: 3, hash(license):  3
  8:    NULL
  9:    NULL
 10: license: FTK123, num: 1, hash(license): 10
 11:    NULL
 12:    NULL
Enter license number ---> quit
% cat licenses
SSR474 1
ULL585 1
UBT878 1
KGB209 1
TEA311 3
MUK772 1
XYZ333 3
FTK123 1