ITM 207 Chapter 7

Steps To Solve Problems

1. Understand the problem 2. Devise a plan 3. Carry out the plan 4. Look back

Record

A collection of related fields that make up a single database entry A named heterogeneous collection of items in which each individual item is accessed by NAME e.g. name, age, hourly wage makes up a single entry for this

Array

A named homogeneous collection of items in which an individual item is accessed by it's position (index) As data is being read, a counter is updated so we know how many data items are being stored

Algorithm

A set of unambiguous instructions for solving a problem or a subproblem in a finite amount of time using a finite amount of data 2 Types of steps: Abstract, Concrete

Concrete Step

Algorithmic step where all the details ARE specified

Abstract Step

Algorithmic step where all the details AREN'T specified

Control Structure

An instruction that determines the order in which other instructions in a program are executed

Computer Problem Solving Phases

Analyze and Specification Phase (analyze/specify) Algorithm Development Phase (develop/test) Implementation Stage (code/test) Maintenance Phase (use/maintain)

Summary of Methedology

Analyze the problem List the main tasks List the remaining tasks Re-sequence and revise as necessary

Problem Solving Strategies

Ask questions - Never reinvent the wheel Divide and Conquer

Sequential Search Of An Unsorted Array

Examines each item and compares to each one being searched for If matched, item is found If not, search continues till item is found or entire list has been searched

Selection Sort

Find what data entry comes first Move it to the top Repeat sequence

Object-Oriented Design

Focuses on data involved in the situation

Top Down Design

Focuses on tasks to be completed

Paramter

Identifiers listed in parentheses beside the subprogram declaration also known as FORMAL __________

Argument

Identifiers listed in parentheses on the subprogram call sometimes refer to ACTUAL PARAMTERS

Binary Search

List must be sorted Search begins in the middle Searches one half at a time If found, other half is eliminated If not found, unexamined half is searched

Re-sequence And Revise As Necessary

Process ends when all steps are completed

Composite Data Types

Records, and Arrays

Write The Remaining Models

Restate each abstract model as a list of tasks, give each a task a name

List The Main Tasks (Become main modules)

Restate each problem as a list of tasks, give each task as a name

Bubble Sort

Start from the bottom Compare first 2 items Switch occurs so the higher value is above Starting with the last list pair, compare successive pairs of elements

Insertion Sort

Start from the top Compare first 2 items Keep the highest value on top

Problem Solving

The act of finding a solution to a perplexing, distressing, vetting, or unsettled question

Count-Controlled Loops

The count is kept in a variable (index/count) Number of repetitions is known before the program is executed

Event-Controlled Loops

The number of repetitions is controlled by an event that occurs within the body of the loop itself

Analyze The Problem

Understand the problem, devise a plan of attack

Sequential Search Of A Sorted Array

We can stop searching when we pass the place where the item can be