Iteration: FOR

FOR counts

• A count-controlled loop runs once for each integer from the start to the end, inclusive.
• The counter is an INTEGER.
• It is good practice to repeat the counter's name after NEXT.

DECLARE Total : INTEGER
DECLARE I : INTEGER
Total ← 0
FOR I ← 1 TO 5
  Total ← Total + I
NEXT I
OUTPUT Total

STEP changes the jump

• STEP sets the gap between values. It can be negative.
• If the start is already past the end in the step's direction, the body does not run.

DECLARE I : INTEGER
FOR I ← 5 TO 1 STEP -2
  OUTPUT I
NEXT I

Watch out

• NEXT I must name the counter of this loop.
• The body is indented. NEXT lines up with FOR.

Common mistakes

Before a loop, distinguish DECLARE Count : INTEGER (choose a type) from Count ← 0 (store a value). The loop header changes the counter; the body changes the result you are computing.

• 1 TO 5 includes both 1 and 5.
• Do not change the counter yourself inside the body.

Now you try

• Use a FOR loop to print a run of numbers.

Independent transfer

The final task has no supplied algorithm. Plan its inputs, processing and outputs, then solve it before opening support. Check more than the sample case.