Return Values CS Thinking Example 4

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

Example 4

medium
What is the output of this program? FUNCTION double(n) RETURN n * 2 END FUNCTION FUNCTION addThree(n) RETURN n + 3 END FUNCTION SET result = addThree(double(4)) OUTPUT result

Solution

  1. 1
    Step 1: Evaluate the inner call first: double(4) → RETURN 4 * 2 = 8.
  2. 2
    Step 2: The return value 8 is passed to addThree: addThree(8) → RETURN 8 + 3 = 11.
  3. 3
    Step 3: result = 11. OUTPUT 11.

Answer

11. Nested function calls evaluate from the inside out — the inner function's return value becomes the argument to the outer function.
Composing functions by using one function's return value as another's argument is a fundamental pattern. The key is evaluating the innermost call first and working outward.

About Return Values

The value that a function sends back to the code that called it, specified by the return statement. When a function executes a return statement, it immediately stops running and passes the specified value back to the caller, where it can be stored, used in expressions, or passed to other functions.

Learn more about Return Values →

More Return Values Examples

Example 1 medium

FUNCTION square(n): RETURN n * n. What is the output of: SET result = square(4) + square(3). OUTPUT

Example 2 medium

What is the difference between a function that returns a value and one that just prints? Compare: FU

Example 3 medium

FUNCTION max(a, b): IF a > b THEN RETURN a ELSE RETURN b. What is max(max(3, 7), max(5, 2))?

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