5.1 Procedures and functions are coding constructs often used as part of modular programming - NSC Information Technology - Question 5 - 2022 - Paper 2

One key difference is that a procedure does not return a value, while a function must return a value, often using that value as part of an expression.

This statement is invalid because you cannot assign an integer value (2) to a Boolean variable (X); Boolean variables must only hold values of true or false.

This statement is valid as string comparisons are permissible in programming languages, allowing for lexicographical comparisons.

Defensive programming is a technique used by programmers to anticipate and mitigate potential errors that could cause a program to fail. This involves creating code that checks assumptions, validates inputs, and handles exceptions gracefully to ensure robust performance.

An overflow error can occur when a value being stored in a data type exceeds the maximum limit of that data type. For instance, trying to store a value larger than what an integer can hold will trigger this error.

To prevent runtime errors, programmers can utilize data validation techniques. This involves checking that input values fall within expected ranges before processing them.

The purpose of a constructor method is to initialize an object. It sets default values for data attributes and prepares the object for use upon its creation.

An accessor method from the class diagram is getCompanyName(), which allows retrieval of the company name attribute.

The attribute for which the use of a mutator method will be the least applicable is CompanyNum, as it uniquely identifies the company and should not be changed once set.

Using a mutator method on the CompanyNum attribute is not advisable as this number is a unique identifier for the company. Changing it could lead to data integrity issues and confusion in identifying the company.

In the class diagram, the method toString() is specified as public, which is appropriate. However, attributes such as CompanyNum and NumberOfEmployees should ideally be private to protect their integrity.

Allowing direct public access to sensitive attributes can lead to unintended modifications. For instance, if the CompanyNum could be altered from outside the class, it might result in references to wrong entities or corruption of object state.

A sentinel controlled loop is preferred when the number of iterations is unknown ahead of time and you want to continue looping until a specific condition is met, allowing for more flexible control over loop execution.

Here’s how you could rewrite the provided code using a WHILE loop:

  iNumber := RandomRange(1,11);
  While (iNumber > 5) OR (iNumber < 8) do
    iNumber := RandomRange(1,11);