Pseudocode Flashcards
Analysis
The analysis stage uses abstraction and decomposition tools to identify the purpose of the program
Abstraction keeps the key elements used to solve the problem and discards any un necessary details
Decomposition breaks down the problem into smaller parts and then divides those parts into subparts to make each one of them very easy to solve
Design
When the design stage is done, a programmer should know what is to be done (all the tasks that need to be solved , how to complete each task and how each task is connected)
It can be documented using flowcharts, pseudocodes and structured charts
Coding and Iterative Testing
In this step the program or programs are developed
Each module or part of the program is written using a suitable programming language and is then tested
Each module is tested and code amended until each module performs as intended
Testing
In this phase the completed program or programs is tested using many sets of test data to ensure that everything is working smoothly and all tasks are being completed as mentioned in the Design phase
Computer Systems, Sub-Systems and Decomposition
Computer systems are made up of software, hardware, data, communications and people
They can be divided into sub-systems and those into further sub-systems until each sub-system carries out a single condition
Computer systems can be big or small, phone alarm is an example of a very small computer system, weather forecast is an example of very large international computer system
The Computer System and its Sub-Systems
computer systems are often divided into sub systems, this division can be shown using top-down design to create structure diagrams that show the modular construction of the system.
Top-down design is the decomposition of a computer system into a set of subsystems, until each sub-system just performs a single action.
This structured approach works for the development of both large and small computer systems. In larger computer systems it allows for each individual component to be tested simultaneously
Decomposing a Problem
inputs – the data used by the system that needs to be entered while the system is active
processes – the tasks that need to be performed using the input data and any other previously stored data
outputs – information that needs to be displayed or printed for the users of the system
storage – data that needs to be stored in files on an appropriate medium for use in the future.
Decomposing a Problem
inputs – the data used by the system that needs to be entered while the system is active
processes – the tasks that need to be performed using the input data and any other previously stored data
outputs – information that needs to be displayed or printed for the users of the system
storage – data that needs to be stored in files on an appropriate medium for use in the future.
Structure Diagrams
Structure diagrams are hierarchal and show how a computer system can be divided into sub-sections, each section giving a more detailed breakdown
Flowchart
flowchart shows the steps required to complete a task and their order through a diagram
These ordered steps are called the algorithm
Pseudocode
Pseudocode is a simple method of showing an algorithm and describes it using English keywords that are similar to those used in programming languages.
Data items in pseudocodes are given meaningful names like variables in coding
Validation
Validation is the automated checking by a program that data is reasonable before it is accepted into a computer system.
» range checks » length checks » type checks » presence checks » format checks » check digits.
Verification
Verification is checking that data has been accurately copied from one source to another
» Double entry
» Screen/visual check
Test Data
A set of test data is all the items of data required to work through a solution
a set of test data that a program is expected to work with is called normal data
In order to test for termination use test data that would
be rejected by the solution as not suitable if the solution is working properly. This type of test data is called abnormal test data.
Extreme data is the maximum and minimum of normal data
Boundary data is used to establish where the largest and smallest values occur
Writing and Amending Algorithms
Purpose Stepwise refinement-Input, Processing, Storage, Output Decide on data storage and display Structure Diagram Pseudocode Flowchart Use Several Data Sets Error Detection
