Problem modeling, Algorithm analysis, Basis Flowchart and block diagram

Six Steps of Problem Solving §

1. Identify the problem
2. Understand the problem
3. Identify alternative ways to solve the problem
4. Select the best way to solve the problem from the list of alternative solutions
5. List instructions that enable you to solve the problem from the list of alternative solutions
6. List instructions that enable you to solve the problem using the selected solution.
7. Evaluate the solution

Algorithmic solutions is are those which can be solved using a specific amount of steps and are not dependent on senses, experience, perception or opinions

What problem can be solved by computer ? §

• When the solution can be produced by a set of step-by-step procedures or actions.
• This step-by-step action is called an algorithm.
• The algorithm will process some inputs and produced output.
• Solving problem by computer undergo two phases:
  • Phase 1:
    • Organizing the problem or pre-programming phase.
  • Phase 2:
    • Programming phase.

Pre Programming Phase §

1. Analyzing the problem.
2. HIPO Hierarchy Input Process-Output or PAC Programming Analysis Chart (PAC)
3. Developing the Input-Process-Output (IPO) Chart.
4. Drawing Program flowcharts.
5. Writing Algorithms.

PAC Problem Analysis Chart §

• Emphasis on Data? eg

Data	Processing	Output
Hours work, pay rate	Salary = Hours work * payrate	Salary

Input Process Output (IPO) Chart §

• Extends and organizes the information in the Problem Analysis Chart. • It shows in more detail what data items are input, what are the processing or modules on that data, and what will be the result or output. • It extends information from PAC. eg

Input	Processing	Module	Output
- Hours Worked	- Enter Hourly Worked	1100	- Net pay
- PayRate	- Enter Pay Rate	1200
- Deductions	- Calculate Gross Pay	1000
	- Enter Deductions	2100
	- Calculate Net Pay	2000
	- Print cheque	3000
	- End	0000

• Emphasis on Input

Q Write a Input Process Output (IPO) to convert the distance in miles to kilometers where 1.609 kilometers per mile

Input	Processing	Module	Output
- Distance in Miles	- Enter Distance	1000	- Distance in kilometers
	- Kilometer = 1.609 x distance	2000
	- Display Kilometers	3000

Q Write a input process Output (IPO) to find an area of a circle where area = pi * radius * radius

Input	Processing	Module	Output
- radius	- Enter Radius	1000	- Area of a circle
	- Area = 3.14 x Radius x Radiu	2000
	- Display area	3000
	- End	0000

Question

Q Write an Input Process Output (IPO) that asks a user to enter the distance of a trip in miles, the miles per gallon estimate for the user’s car, and the average cost of a gallon of gas. Calculate and display the number of gallons of gas needed and the estimated cost of the trip

PAC §

Data	Processing	Output
distance, miles_per_gallon, cost_per_gallon inputted by user	Enter cost_per_gallon	gallons
	Enter distance	cost
	Enter miles_per_gallon
	- Calculate gallon = distance/miles_per_gallon
	- Calculte cost = gallon * cost_per_gallon

IPO §

Input	Processing	Module	Output
distance	Enter miles_per_gallon	1100	gallons
miles_per_gallon	Enter distance	1200	cost
cost_per_gallon	- Calculate gallon = distance/miles_per_gallon	1000
	Enter cost_per_gallon	2100
	- Calculte cost = gallon * cost_per_gallon	2000
	Display gallons	3000
	Display cost	4000
	End	0000

Flowchart §

%%🖋 Edit in Excalidraw, and the dark exported image%%

Question

Make a calculator that demands two numbers, and outputs. +, -, *, \of the two

Input	Processing	Module	Output
num1	Enter num1	1100	subtraction
num1	Enter num2	1200	addition
	- Calculate subtraction = num1 - num2	1300	multiplication
	- Calculate addition = num1 + num2	1400	division
	- Calculate multiplication = num1*num2	1500
	- Calculate division = num1/num2	1600
	Display subtraction, addition, multiplication, division	2000
	End	0000

Question

Simple calculation of volume

Input	Processing	Module	Output
	set height = 25	1100	volume
	set length = 40	1200
	set width = 18	1300
	Calculate $vol=height\ast length\ast width$	2000
	Display vol	3000
	End	0000

Question

Calc of Hyp using side1 and side2

Input	Processing	Module	Output
	set side1 = 10	1100	hyp
	set side2 = 8	1200
	Calculate $hyp=sqrt(side{1}^2+side{2}^2)$	2000
	Display hyp	3000
	End	0000