Nested decisions

One mark, three outcomes

• A mark of 80 or more is a distinction, 50 or more is a pass, and anything lower is a fail.
• One IF has two paths. The second decision goes inside the ELSE, as its own IF.
• Each IF has its own ENDIF. Indent the inner one so you can see which ELSE it belongs to.

DECLARE Mark : INTEGER
Mark ← 72
IF Mark >= 80
  THEN
    OUTPUT "Distinction"
  ELSE
    IF Mark >= 50
      THEN
        OUTPUT "Pass"
      ELSE
        OUTPUT "Fail"
    ENDIF
ENDIF

Count the marks that count

• A validation tally walks the list and adds 1 only when the value is in range.
• The range test is the AND from the previous lesson, inside the loop.

DECLARE Mark : ARRAY[1:4] OF INTEGER
DECLARE I, Count : INTEGER
Mark[1] ← 80
Mark[2] ← -1
Mark[3] ← 100
Mark[4] ← 40
Count ← 0
FOR I ← 1 TO 4
    IF Mark[I] >= 0 AND Mark[I] <= 100
      THEN
        Count ← Count + 1
    ENDIF
NEXT I
OUTPUT Count                 // → 3

Watch out

• The inner IF starts on the line after ELSE. It is not written on the ELSE line.
• Close the inner ENDIF before the outer one. The last ENDIF belongs to the first IF.

Common mistakes

• An ENDIF in the wrong place closes the outer test and leaves the inner one open.
• A mark of exactly 50 is a pass, and exactly 80 is a distinction. The tests use >=.

Now you try

• The first two tasks are nested decisions. The third counts with AND.
• Press Check answer to test it.