Program Design (Cambridge (CIE) AS Computer Science): Exam Questions

A program contains six modules with headers as follows:

Module Connect() will call either Activate() or Sync(). This is decided at run-time.

Complete the structure chart for these modules.

Explain the meaning of the curved arrow symbol used in the diagram in part (a).

A coffee shop runs a computerised loyalty card system.

Customers are issued with a loyalty card with their name together with a unique customer ID.

Loyalty points are added to their card each time they spend money at the shop.

The following information is stored for each customer: ID, name, home address, email address, mobile phone number, date of birth, number of points, date of last visit and amount of money spent at last visit.

A new module will generate a personalised email message to each loyalty card customer who has not visited the coffee shop in the last three months. The message will include a unique voucher code which can be used to authorise a discount if the customer goes to the shop within the next two weeks.

It is decided to adopt a formal program development life cycle model for the development of the new module.

The analysis of the new module is complete and the project moves on to the design stage. During this stage all the necessary algorithms and module designs will be defined.

State three other items that will be defined for the new module during the design stage.

Part of the coffee shop program contains three program modules as follows:

Module Init() has no parameters and returns a Boolean.

Module Reset() takes a string as a parameter and returns an Integer.

Module Check() repeatedly calls Init() followed by Reset().

Draw a structure chart to represent the relationship between the three modules, including all parameters and return values.

A coffee shop owner wants to introduce a computerised loyalty card system.

A programmer discusses the details of the system with the shop owner.

The shop will give each customer a loyalty card that displays a unique customer ID as a bar code. A customer will be able to present their card each time they make a purchase. The system will scan the bar code, calculate points, and add them to the customer’s total. When the customer next makes a purchase and presents their card, they will have the option to exchange points for a discount.

The designer decides that this activity will be handled by a new module. Decomposition will be used to break the problem of designing the new module down into sub-problems (sub-modules).

Identify four sub-modules that could be used in the design of the new module and describe their use.

A fitness club has a computerised membership system. The fitness club offers a number of different exercise classes.

The following information is stored for each club member: name, home address, email address, mobile phone number, date of birth and the exercise(s) they are interested in.

The structure chart illustrates part of the membership program:

Data item notes:

• Name contains the name of a club member

• P1 and T1 are of type real.

Explain the meaning of the diamond symbol (labelled with the letter A) in the chart.

A fitness club has a computerised membership system.

The system stores information for each club member: name, home address, email address, mobile phone number, date of birth and exercise preferences.

Many classes are full, and the club creates a waiting list for each class. The club adds details of members who want to join a class that is full to the waiting list for that class.

When the system identifies that a space is available in one of the classes, a new module will send a text message to each member who is on the waiting list.

A different part of the program is represented by the following state‑transition diagram.

(i) Complete the table to show the inputs, outputs and next states.

Assume that the current state for each row is given by the ‘Next state’ on the previous row. For example, the first Input‑A is made when in state S1.

If there is no output for a given transition, then the output cell should contain ‘none’.

The first two rows have been completed.

(5)

(ii) Identify the input sequence that will cause the minimum number of state changes in the transition from S1 to S4.

(1)

A teacher is designing a program to process pseudocode projects written by her students.

Each student project is stored in a text file.

The process is split into a number of stages. Each stage performs a different task and creates a new file.

For example:

Suggest a reason why the teacher’s program has been split into a number of stages and give the benefit of producing a different file from each stage.

Seven program modules form part of a program. A description of the relationship between the modules is summarised below. Any return values are stated in the description.

Parameters in the table are as follows:

• Par1 and Par3 are of type string.

• Par2 is of type integer.

Draw a structure chart to show the relationship between the seven modules and the parameters passed between them.

An algorithm is represented by a state-transition diagram.

The table shows the inputs, outputs and states for the algorithm:

Complete the state-transition diagram to represent the information given in the table.