For Loop CS Thinking Example 3

Follow the full solution, then compare it with the other examples linked below.

Example 3

medium
Write a FOR loop that calculates 5!=5×4×3×2×15! = 5 \times 4 \times 3 \times 2 \times 1.

Solution

  1. 1
    Step 1: SET result = 1. FOR i = 1 TO 5: result = result * i.
  2. 2
    Step 2: Trace: 1*1=1, 1*2=2, 2*3=6, 6*4=24, 24*5=120.

Answer

120120. SET result = 1. FOR i = 1 TO 5: result = result * i.
The accumulator pattern works for products too — initialise to 1 (the multiplicative identity) and multiply each value in the loop.

About For Loop

A control structure that repeats a block of code a specific number of times or once for each item in a collection. The loop variable is automatically set to each successive value in the range or collection, eliminating the need to manually update it.

Learn more about For Loop →

More For Loop Examples

Example 1 easy

Trace: FOR i = 0 TO 4: OUTPUT i * i.

Example 2 medium

Convert this FOR loop to a WHILE loop: FOR i = 1 TO 5: OUTPUT i.

Example 4 medium

What does this code output? SET scores = [85, 92, 78, 95, 88] SET highest = scores[0] FOR i = 1 TO

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Related Concepts

IterationWhile LoopArray