Passing by reference VS Passing by value

Question 1

What is passing by value?

Answer 1

The value created for the subroutine is a copy of the original value.

Question 2

What is passing by reference?

Answer 2

A pointer that contains the memory address of the original variable is created

This means that any change made to the variable in the subroutine also affects the original variable.

Question 3

Features of passing by value

Answer 3

The copied value has its own separate memory

Seen more in newer programming languages

Question 4

1 positive and 1 negative of passing by value

Answer 4

+ The copied variable and the original can be given the same identifier

• Creates inconsistency between the two variables

Question 5

When would you pass by reference?

Answer 5

If the original value needs editing

Question 6

When would you pass by value?

Answer 6

If it’s local and merely referenced

Question 7

Features of passing by reference?

Answer 7

Uses a pre-existing memory location to store the memory address of the value.

Any edits directly affect the variable

Question 8

1 Positive and 1 negative of passing by reference

Answer 8

+ Requires less space than passing by value

• Entails implicit dependency, which is considered bad practice.

Question 9

How is implicit dependency triggered in passing by reference?

Answer 9

If you pass a local variable by reference and then assign to it, the result is a direct change to the caller’s variable, not to what its pointing to.