Writing a useful procedure

Develop a procedure from a clear contract: what inputs are allowed, what result is returned and what happens on boundaries or empty collections. Parameters should represent the differences between intended uses. Merely listing a parameter does not make the body general if it still uses a fixed constant instead.

A useful list procedure can sequence initialization, traverse each element, select qualifying values and return a result after the traversal. Write the contract first, then test calls showing that changing a relevant argument changes behaviour. Keep the empty-list result and inclusive/exclusive boundaries explicit.

recommend(values,low,high)returns entries between low and high inclusive, requiring low≤high.

result ← []
FOR EACH value IN values
{ IF(value ≥ low AND value ≤ high) { APPEND(result,value) } }
RETURN(result)

1. For[1,5,8,5,10]and bounds 5…8,the result is[5,8,5].
2. The same list with 8…10 returns[8,10].
3. An empty list returns[]because initialization occurs before the loop.

Claim: A parameter is meaningful even if the body overwrites or ignores it.

Changing only that argument must be able to change the relevant behaviour on some valid input.

Give two calls on one list demonstrating that high affects the result.

Work with a partner. Make a prediction, compare your reasoning, then identify the rule that supports your answer.

Modify a minimum-only filter to use both inclusive bounds and explain each construct.

Why state low≤high as a precondition?

Write your reasoning before comparing with a classmate. If your teacher assigned this task, submit it through My classes to save your work and receive feedback.