 Software Development Life Cycle  Software Development Tools  High Level Programming:  Structures  Algorithms  Iteration  Pseudocode  Order of Priority and Relational Operators

A Dance In The Dark Every Monday

Analysis is about understanding the problem. Start by describing the problem, as you see it, in your own words as clearly and concisely as possible.  Identify all required inputs. (external information)  Identify all required processes. (calculations, decisions, comparisons)  Identify all required outputs. (anything which must be shown on the screen or output in any other way)

At this stage the designers will set out how the problem will be solved. They will design various aspects of the program using:  storyboards  testplan  pseudocode  graphical design notation (flowcharts)  shows the overall structure of the program clearly

Actually writing all the program code using a software development program e.g. Java, C++, Visual Basic. Software development programs provide a text editor that you use to write high level language code

 normal conditions the program does what it should do with normal input e.g. the user has to enter a number between 1 and 100  extreme conditions the program can handle situations that are at the edge of what would be considered normal  exceptional conditions it can handle inputs that it has not been designed to cope with e.g. A program is being written to record scores rolled on a six-sided dice the most suitable set of test data : 3, 1, 0, 7, 6, 2

The types of documentation generated at this stage often include:  technical guide  information about the spec of computer required  user guide  step by step guide on how to use the program  description of the features of the software

 checking whether the program is readable  does the solution solve the problem  the issues encountered  the issues outstanding  recommendations for improvement

program maintenance may be required when  new bugs are uncovered by the end-user  new requirements are identified  at a later date the client requires the original solution to be integrated with other systems

Translates high level languages (written by humans) into machine code (understood by processors) There are two main types of translator programs.  Compiler  translates a program into machine code (commands that are written in ones and zeroes)  Interpreter  does the same as a compiler but one line at a time

Small programs called macros can be developed within some application packages e.g. Word Processing, Spreadsheets. The macro is actually coded in a scripting language called Visual BASIC for Applications(VBA) A Macro is a set of commands activated by a single keystroke.

There are some standard pre-defined functions that you may want to use in your programs. Pre-defined functions: greatly speed up program development  Int  takes a number and removes any fractional part leaving the whole number part  isKeyDown  retrieves keyboard input

An algorithm is a finite sequence of steps that solves a specific problem. For this unit, you need to know about 4 standard algorithms.  finding a minimum  finding a maximum  counting occurrences  linear search

Example: a list of daily midday temperatures recorded at a weather station during February 2003 The find a minimum algorithm would search through all the daily temperatures in the list, and find the lowest one i.e. (2°C) date temperature (°C) date temperature (°C)

 find maximum works its way through a list of numbers and finds the number with the highest value i.e. (12°C)  counting occurrences  counts how many occurrences of a given value there are in the list  Linear search  searches through a list looking for a particular item and reports where the item is found

All of the standard algorithms which you met in the last slides operate on a list of data items. We will see how a computer program can store a list of items

Suppose a program was required which would prompt the user to enter and store the names and scores for nine dart players. Variables required: first_name, second_name, third_name, fourth_name …… ninth_name (all strings) first_score, second_score, third_score, fourth_score …… ninth_score (all numbers).

Instead of creating 18 individual variables you create 2 arrays:  An array of strings:  string[] names = new string[5];  An array of numbers  int[] marks = new int[5];

 Fixed loop  the number of times a section of code is to be repeated is fixed in advance For(i=0; i<5; i++) { Lines of code }  Conditional loop  A section of code in a program is to be repeated until a particular item of data is entered by the user while (i < 10) { Lines of code }

 Arithmetic operators +, -, *, / Which one of the following would be the output from the line of program code below? PRINT * 4 –

== != > = <= A ticket program will give a discount if the person is under 16 or if the person is 65 and over Age > 65 AND age < 16 Age > 65 OR age < 16 Age > = 65 AND age < 16 Age > = 65 OR age < 16

Mix of English and programming language and can help when converting to code let score be 24 if score is greater than or equal to 30 display “A Pass” if score is greater than or equal to 24 and less than 30 display “B Pass” if score is greater than or equal to 16 and less than 24 display “C Pass” if score is less than 16 display “Fail”

In the code sample above, what type of statement is the first line? let score be 23 Conditional loop Fixed loop Conditional statement Assignment What is the output on screen from the code section above? A Pass B Pass C Pass Fail What program construct is being used in the section of pseudocode shown above? A fixed loop A conditional loop Conditional statements An arithmetical operation