Data types, variables and operations: แบบฝึกหัด

A developer uses the identifier total_interest_rate instead of x in their program code. Why is the use of meaningful identifier names considered good practice in programming?

A string S has the value "AQA_CS_2024". What is the result of the operation SUBSTRING(4, 2, S)?
(Assume the first character is at position 0, and the parameters are: start index, length)

In the context of the Unified Modelling Language (UML) for Object-Oriented Design, how are composition and aggregation relationships visually distinguished in a class diagram?

In a programming language, the operation 17 MOD 5 is performed. What is the result of this integer division remainder operation?

Consider a functional programming context. Given a list \( [4, 3, 5] \), which of the following represents the list using head:tail notation?

In a programming language, what is the result of the operation \( 17 \text{ DIV } 5 \)?

A string variable s has the value "AQA2024". What is the result of the operation SUBSTRING(s, 0, 3)? (Assume 0-based indexing and that the third parameter is length).

In Object-Oriented Programming, a class Car and a class Engine are related such that the Engine is a part of the Car, and if the Car is destroyed, the Engine is also destroyed. Name this specific type of relationship.

A subroutine is defined to calculate the area of a circle using the formula \( Area = \pi \times r^2 \).

(a) Define the term subroutine.
(b) Explain the difference between a procedure and a function.

Consider the following pseudocode snippet:
x = "AQA Computer Science"
y = 7

(a) Describe the result of the following string operations:
i. substring(0, 3) of x
ii. length of x
(b) Explain the difference between global variables and local variables, stating why using local variables is considered good practice.