Part 1 - Lecture 5

What is a Bit in programming

a single one or zero

contraction of “binary digit”, also convenient for logical and algebraic information (Boolean “true”/”false”, pos/neg)

What is a Byte in programming

it is 8 bits

XOR (exclusive OR)

returns TRUE if either A or B is true, but not both

NAND (NOT AND)

returns TRUE unless both A and B are TRUE

NOR (NOT OR)

returns TRUE only when both A and B are FALSE

What is Imperative and Procedural Programming

Ex: FORTRAN, BASIC, Pascal, C, C++

Programs are a list of tasks, subroutines

Like a recipe: each step is a sequenced instruction

Procedural languages allow programmer to define functions, subroutines (procedures) and reuse throughout the program

What is Object-Oriented Programming

Ex: Java, Objective-C, VisualBasic.NET

Programs are a collection of interacting objects

Objects can have independent functions, characteristics, and states

A Class is a “blueprint” for an object – it describes the functions and characteristics that all objects in that class share in common

•Ex: “the class of all dogs”

A specific member of a class is an Instance

• Ex: “a beagle is an instance of a dog”

What is Software Development Life Cycle (SDLC)

Need for standard approach to

• Determine scope

• Organize programming tasks

• Determine testing requirements

• Manage resources & time commitments

• Deliver software on a reproducible schedule

The different phases of Software Development Life Cycle (SDLC)

Planning

Software Implementation (what we often refer to as “Software Development or Design”)

Testing – Verification vs. Validation

Documentation

Deployment (what we often refer to as “Implementation”)

Maintenance

SDLC Methodologies: Waterfall

Move to next phase only when prior phase is done

SDLC Methodologies: Spiral

“Risk oriented” software development

Development broken into smaller efforts

Each subproject designed to tackle an area of high-risk

Advantages: highest risk is tackled early on, when change is less expensive

SDLC Methodologies: Agile

High focus on very small steps, frequent loops

Regular testing and regular demo to users

Advantage: Extremely flexible; assumes that clients will change requirements and is equipped to adapt to unpredicted challenges

Client can change their mind on the spot and it will be easier to implement

Regression Testing

Regression is a new defect revealed with the addition of a new functionality

Ex: you add a new feature to a program, now an older feature stops working as intended – that’s a regression

Types of Qualitative Data:

Nominal aka “Categorical”

Think “data with names”

Mutually exclusive, unordered, discrete categories of data, such as patient smoking status

Mode (most frequently occurring value) is the only measure of central tendency

Types of Qualitative Data:

Ordinal

Think “ordered data”

• Data that have a natural ordering

• Ex: “Small”, “Medium”, “Large”

Types of Quantitative Data:

Interval

Data where the intervals between values represent the same distance

Example: Year, Temperature. The difference between 32°F and 33°F is the same as the difference between 76°F and 77°F

Types of Quantitative Data:

Ratio

Allows for additional comparison because “zero” means something and is not arbitrarily chosen

Ex: Area, distance.