Tuesday, March 12, 2013

USING COMPUTERS TO SOLVE PROBLEMS

USING COMPUTERS TO SOLVE PROBLEMS

USING COMPUTERS TO SOLVE PROBLEMS 

As an examination candidate you have to understand how computers are used to solve problems. Assessment Objective A of the National Criteria for GCSE Computer Studies says:

The candidate should be able to demonstrate a knowledge and understanding of the techniques needed to solve problems related to practical applications.'

(To find out about the National Criteria see the section on the GCSE on page xiii.)

INFORMATION PROCESSING APPLICATIONS

As hardware and software become topic , more and more problems are seen to involve information processing. The range of applications for computers and similar equipment increases all the time.

Examples could be taken from almost any human activity. Few people 30 years ago would have thought that computer technology would be used, for example, in:

1 Operating a camera-many cameras contain a microprocessor.

2 Writing a letter-word processors are now commonplace.

of this topics give details of some of the wide variety of ways in which computers are used. This unit deals with the general methods of using computers to solve problems.

STEPS IN PROBLEM SOLVING

Using a computer to solve a problem involves far more than just writing a program. In fact many computer applications are carried out without writing new programs. Exisiting software is used if possible.

Solving a problem may be seen in three main stages:

1 Defining exactly what the problem is.

2 Designing a solution to deal with it.

3 Putting that solution into practice.

In solving an information processing problem we should define:

1 The data which is to be input.

2 The data which is to be output.

3 The data which is to be stored as files.

4 The processing tasks to be carried out.

Example of a problem and a solution to it

In a particular school the pupils are divided into groups for registration and tutorials. A school list is produced by the office. This gives the names of all the pupils, arranged into tutor groups, for example :

1Sm

1Th

1Wi

Mr smith Room 40

Adams, jermy D

Arnold, Helen B

Biggs, freda

Mr Thomas room 41

Arden , peter

Batten, john N

Bostock, jean V

Miss Williams room 4

Baines, june W

Betterton, bery1

Daines, peter C

and so on …

The problem is it is difficult to use this list to find a pupil if his or her tutor group is not known. It would be much better to have two lists- the present one and another one which is alphabetical. The office staff say it would be too much work for them to produce both.

The proposed solution is to cut down the work involved by paying for a computer to be introduced. It is decided to type in data for each pupil Most of this will be done at the start of a school year and the data will be stored on files. These can then be updated during the year for new pupils or those who leave. It would be too much work to type in for all pupils their tutor's name, their tutor group name and their room number. Instead a code will be used for the pupil's tutor.

The following will be involved:

1 Three sets of input data:

(a) The full name and tutor for each pupil. In fact the tutor's complete name will not be typed

but just a two-letter code for it e.g. Mr Smith will be Sm.

(b) The full name, tutor group name and room for each tutor.

(c) Choices of what lists are to be produced.

2 Two lists as output data:

(a) A list of all the tutor groups with the pupils in them (like the one the office produced

originally).

(b) A list of all the pupils in the school in alphabetical order. Each name will be followed by the tutor's name, the tutor group name and the room they are in.

3 Two sets of data stored as files:

(a) A file storing for each pupil the full name and two-letter tutor code.

(b) A file storing for each tutor the two-letter code. full name, tutor group name and room.

4 Five main processing tasks for the computer:

(a) Inputting the pupil data and storing it in the pupil file.

(b) Inputting the tutor data and storing it in the tutor file.

(c) Updating these files when necessary.

(d) Sorting the pupils into tutor groups and printing the list of pupils in their groups.

(e) Sorting the pupils into alphabetical order and printing the alphabetical list.

To explain fully how the problem in the previous example was solved we would also have to describe:

1 Who is in charge of producing the lists and how it is organized.

2 Where the input data comes from i.e. how it is collected.

3 Who types in the data and produces the lists and how they communicate with the computer.

4 What computer equipment is used.

5 What programs are used and whether they are bought or specially written.

If we did this we would have described the information processing system for dealing with the problem.