Trends in Software Development 📶

Program

set of instructions telling computer what to do to solve particular problem

Programming paradigms

approaches to programming e.g procedural or object orientated

Procedural programming

• programmer sets out step by step instructions in source code

• sequential

• top down design

• solutions to sub problems are written as methods

• program is made up of number of methods called repeatedly

Sequential

instructions carried out one after another

Top-down design

breaking complex problems into smaller sub problems

Examples of procedural programming

COBOL or FORTRAN

Object orientated programming

• programmer creates objects which contain properties and methods

• classes

• inheritance

• encapsulation

Classes

acts as template defining properties and methods for group of objects

Inheritance

allows a class to build off another so only differences need to be coded

Encapsulation

hides the data of an object so can only be accessed through methods within object

Examples of object orientated programming

C# or C++

Advantages of object orientated programming

• code can be programmed and maintained independently

• code for object can be reused in different programs

• details of implementation are hidden so direct access to object data is reduced

Software development environment (SDE)

software with integrated set of programming tools to build and application

Tools provided by SDE’s

• clipboard, used to copy/paste

• collapsible code sections for easier reading

• line numbering to reference location e.g errors

• code completion tools showing list of available functions

• provide facility to translate program to language specific method of running a program

Machine code

instructions in binary format that can be directly executed by computer

Source code/ high level code

original program code written by programmer, needs translated to execute

High level code translation

program must be translated into binary so the computer can understand and execute the instructions

High level code translation process

• library code is included if used (pre processing)

• lexical analysis converts source code into tokens

• syntax analysis checks grammar rules are followed, must be correct to execute

• semantic analysis ensures variables used have been declared and data types match

• compiler performs multiple passes on code to optimise

• machine code is generated and can be executed

Executing code

instructions loaded into memory and performed

Difference between compiler and interpreter

• compiler translates whole program before its ran, faster e.g C++

• interpreter translates program line by line, slower e.g Python