Parameter passing mechanisms in Compiler Design - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is pass by value in parameter passing?

Pass by value means the function receives a copy of the argument's value. Changes inside the function do not affect the original variable.

beginner

Explain pass by reference.

Pass by reference means the function receives a reference (or address) to the original variable. Changes inside the function affect the original variable.

intermediate

What is the difference between pass by value and pass by reference?

Pass by value sends a copy of data, so changes don't affect the original. Pass by reference sends the actual location, so changes affect the original variable.

intermediate

What does pass by value-result mean?

Pass by value-result copies the argument's value to the function (like pass by value) and then copies it back to the original variable after the function finishes.

advanced

Describe pass by name parameter passing.

Pass by name delays evaluation of the argument until it is used inside the function, substituting the argument expression directly. It behaves like textual substitution.

Which parameter passing mechanism allows the function to modify the caller's variable directly?

A Pass by value-result

B Pass by reference

C Pass by value

D Pass by name

Pass by reference passes the actual address, so changes inside the function affect the original variable.

In which parameter passing method is the argument evaluated only when used inside the function?

A Pass by value

B Pass by value-result

C Pass by reference

D Pass by name

Pass by name delays evaluation until the argument is used, substituting the expression directly.

What happens to the original variable in pass by value-result after the function finishes?

A It is updated with the function's local copy

B It is passed by reference

C It is deleted

D It remains unchanged

Pass by value-result copies back the local changes to the original variable after the function ends.

Which parameter passing mechanism is safest to avoid unintended side effects?

A Pass by name

B Pass by reference

C Pass by value

D Pass by value-result

Pass by value uses copies, so the original data cannot be changed by the function.

Which mechanism can cause unexpected behavior due to multiple evaluations of the argument?

A Pass by name

B Pass by reference

C Pass by value

D Pass by value-result

Pass by name substitutes the argument expression directly, so if used multiple times, it evaluates multiple times.

Explain the main differences between pass by value and pass by reference with examples.

Think about whether the function can change the caller's variable.

Describe pass by value-result and pass by name, and discuss when each might be useful.

Consider copying values vs delaying evaluation.