Algorithm design and problem solving

Program development life cycle

A series of structure steps / activities that are used to produce a system.

Analysis

The first stage of the program development life cycle that involves investigating the problem.

Decomposition

Taking a system and splitting it into smaller sub-systems

Design

The second stage of the program development life cycle

Structure diagram

A hierarchical diagram that shows the decomposition of a system.

Process

An action that is performed

Decompose

The action of performing decomposition

splitting a system into smaller sub-systems

which in turn can be split into smaller sub-systems.

Flowchart

A diagrammatic representation of an algorithm.

Psuedocode

Code-like statements that are used to design an algorithm but do not follow any specific language.

Coding

The writing of a program using one or more programming languages.

Testing

Repeated use of a system to try all different possibilities to make sure the system is fully working and cannot be broken.

Test data

The input data that is used to test a system.

Normal test data

Data that a program should accept.

Abnormal test data

Data that a program should not accept.

Extreme test data

Data that is on the edge of what is allowed.

Boundary test data

Data that is on the edge of being accepted

Search algorithm

A series of steps that searches for a specific value in a set of data.

Sorting algorithm

A series of steps that will rearrange a set of data into an order

Linear search

A search algorithm which visits each item of data in turn to check whether it is the data being looked for.

Bubble sort

A sorting algorithm that moves through the list repeatedly swapping values in pairs.

Totalling

Statements in a program that add together a set of data to produce the total.

Counting

Statements in a program that record how many of something there are.

Minumum

The smallest item in a set of data.

Maximum

The largest item in a set of data.

Average

The mean of a set of values

Validation

The checking of data to make sure it is reasonable and within set bounds.

Range check

A type of validation that makes sure data is between the minimum and maximum.

Length check

A type of validation that checks the number of characters is within a set limit.

Type check

A type of validation that checks data is the correct data type.

Presence check

A type of validation that makes sure data has been entered.

Format check

A type of validation that makes sure the data meets a specific order

Check digit

A type of error detection method that is used for data entry. A calculation is performed on the data entered to create a value. Check digit values are compared to see if the data entered is correct.

Verification

Checking that data is entered accurately

Visual check

Comparing the data entered with the original side-by-side.

Double entry check

Two different people enter the same data which are then compared.

Trace table

A structure to complete when walking through an algorithm manually