Exercism ABAP Track

What is Exercism?

Exercism is a free, open-source platform offering coding exercises across 70+ languages. The ABAP track presents progressively harder katas, each with a suite of unit tests you must make pass. It’s a low-friction way to practise idiomatic ABAP without needing a full SAP system setup.

Each solution lives in a zcl_<exercise>.clas.abap file alongside a .testclasses.abap counterpart — the same structure you’d use in a real system.

Exercises Solved

Exercise	Topic
ITAB Basics	Internal table fill, append, sort, search
ITAB Aggregation	REDUCE, COLLECT, group totals
ITAB Combination	Joining and merging internal tables
ITAB Nesting	Deeply nested structures and table-of-tables
Leap	Modulo arithmetic, COND #
Two Fer	String formatting, optional parameters
Reverse String	Character-level string manipulation
High Scores	Sorting, VALUE #, functional style
Resistor Color	Table lookups, index arithmetic
Scrabble Score	CA operator, character scoring loop
Atbash Cipher	String transformation, cipher logic

Highlights

ITAB Basics — VALUE # and line_index

The ITAB exercises are the meatiest on the track. fill_itab uses VALUE # constructor expressions to populate a structured internal table inline — no APPEND loops:

METHOD fill_itab.
  initial_data = VALUE #(
    ( group = 'A' number = 10 description = 'Group A-2' )
    ( group = 'B' number = 5  description = 'Group B'   )
    ( group = 'A' number = 6  description = 'Group A-1' )
    ( group = 'C' number = 22 description = 'Group C-1' )
    ( group = 'A' number = 13 description = 'Group A-3' )
    ( group = 'C' number = 500 description = 'Group C-2' )
  ).
ENDMETHOD.

Searching uses line_index — a functional alternative to READ TABLE ... TRANSPORTING NO FIELDS that returns the index directly:

METHOD search_itab.
  TRY.
    result_index = line_index( initial_data[ number = 6 ] ).
  CATCH cx_sy_itab_line_not_found.
  ENDTRY.
ENDMETHOD.

Leap — One-liner with COND #

The leap year rules (divisible by 4, except centuries unless also divisible by 400) collapse neatly into a single COND # expression:

METHOD leap.
  result = COND #(
    WHEN year MOD 4 = 0 AND ( year MOD 100 <> 0 OR year MOD 400 = 0 )
    THEN abap_true
    ELSE abap_false
  ).
ENDMETHOD.

No IF, no helper variable — just a direct mapping from condition to result.

Scrabble Score — CA for set membership

Rather than a CASE on individual characters or a lookup table, the score method uses the CA (contains any) operator to test set membership in one expression:

METHOD score.
  DO strlen( input ) TIMES.
    DATA(offset) = sy-index - 1.
    DATA(letter) = input+offset(1).
    DATA(letter_score) = COND #(
      WHEN letter CA 'AEIOULNRSTaeioulnrst' THEN 1
      WHEN letter CA 'DGdg'                 THEN 2
      WHEN letter CA 'BCMPbcmp'             THEN 3
      WHEN letter CA 'FHVWYfhvwy'           THEN 4
      WHEN letter CA 'Kk'                   THEN 5
      WHEN letter CA 'JXjx'                 THEN 8
      WHEN letter CA 'QZqz'                 THEN 10
      ELSE 0
    ).
    result = result + letter_score.
  ENDDO.
ENDMETHOD.

CA returns true if any character in the left operand appears in the right-hand set — making it a compact, readable dispatch table without branching on each letter individually.

Clone into Your System

1. abapGit → New Online Repository
2. URL: https://github.com/CiozZ/exercism
3. Package: $EXERCISM (or any local package)
4. Pull → Activate all
5. Run ABAP Unit on any zcl_* class