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Rating a Shoe. Objectives: Explain how sequence, selection, and iteration are building blocks of algorithms Create equations with two or more variables to represent relationships among quantities. Warm-Up. R = 3 L + 3 P + 2 C + 2 F Solve for R given the following variable values: - PowerPoint PPT Presentation
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Rating a ShoeObjectives:1. Explain how sequence, selection, and
iteration are building blocks of algorithms2. Create equations with two or more
variables to represent relationships among quantities.
Warm-UpR = 3L + 3P + 2C + 2F
1. Solve for R given the following variable values:a) L = 7 P = 4 C = 8 F = 6b) L = 9 P = 8 C = 7 F = 4
2. Describe the relationship between variables L, P, C, & F.c) Do they all affect R equally?d) How does L affect R? e) How does L’s effect on R compare to P’s? f) How does L’s effect on R compare to C’s?
Factors for Choosing ShoesDiscuss with your neighbors:
What factors go into choosing a shoe?
Factors for Choosing ShoesLooks, Price, Comfort, Function
Which Shoe is Better?Shoe 1
Price: $180Comfort: pretty good, a little stiff, not that cushionyLooks: multiple colors, fancy style, famous brandFunction: medium weight, very durable, supportive
Shoe 2
Price: $45Comfort: okay, loose fit, not much cushionLooks: classic, retro, many color choices, minimal styling, famous brand
Function: medium weight, low durability, little support
Shoe 3
Price: $160Comfort: very good, soft, warm Looks: simple, one color, minimal stylingFunction: light weight, not durable, little support
Computing a Problem
1. Identify Factors: Variables
2. Quantify: Numbers & Units
3. Express the Relationship: Equation
4. Algorithm: How my mind does it
5. Coded Algorithm: How computer does it
Which Shoe is Better?
Shoe 1
Price: $180Comfort: pretty good, a little stiff, not that cushionyLooks: multiple colors, fancy style, famous brandFunction: medium weight, very durable, supportive
Shoe 2
Price: $45Comfort: okay, loose fit, not much cushionLooks: classic, retro, many color choices, minimal styling, famous brand
Function: medium weight, low durability, little support
Shoe 3
Price: $160Comfort: very good, soft, warm Looks: simple, one color, minimal stylingFunction: light weight, not durable, little support
How do we compute a rating (0 to 100) for
each shoe?
Which Shoe is Better?Shoe 1
Price: $180Comfort: pretty good, a little stiff, not that cushionyLooks: multiple colors, fancy style, famous brandFunction: medium weight, very durable, supportive
Shoe 2
Price: $45Comfort: okay, loose fit, not much cushionLooks: classic, retro, many color choices, minimal styling, famous brand
Function: medium weight, low durability, little support
Shoe 3
Price: $160Comfort: very good, soft, warm Looks: simple, one color, minimal stylingFunction: light weight, not durable, little support
We need numbers!
We need to Quantify it!Shoe 1
Price: $180Comfort: 6Looks: 8Function: 8
Shoe 2
Price: $45Comfort: okay, loose fit, not much cushionLooks: classic, retro, many color choices, very minimal styling, famous brand
Function: medium weight, low durability, not supportive
Shoe 3Price: $160Comfort: very good, soft, warm Looks: classic, retro, two colors, minimal styling, famous brandFunction: light weight, kinda durable
Rate the factors on a scale from 0-10.
0 = worst 10 = best
We need to Quantify it!Shoe 1
Price: $180Comfort: 6Looks: 8Function: 8
Shoe 2Price: $50Comfort: 5Looks: 7
Function: 6
Shoe 3
Price: $120Comfort: 8Looks: 7Function: 6
But what about the price? It isn’t in the same units as
the others.
We need to Quantify it!Shoe 1
Price: $180 (1)Comfort: 6Looks: 8Function: 8
Shoe 2Price: $50Comfort: 5Looks: 7
Function: 6
Shoe 3
Price: $120Comfort: 8Looks: 7Function: 6
We need to rate the price using the same scale (0 to 10) .
0 = Expensive, 10 = Inexpensive
SelectionIf price <= 20 Then price = 10ElseIf price <= 40 Then price = 9Etc…
Which Shoe is Better?Shoe 1
Price: $180Comfort: pretty good, a little stiff, not that cushiony
Looks: multiple colors, fancy style, famous brand
Function: medium weight, very durable, supportive
Shoe 2
Price: $45Comfort: okay, loose fit, not much cushionLooks: classic, retro, many color choices, minimal styling, famous brand
Function: medium weight, low durability, little support
Shoe 3Price: $160Comfort: very good, soft, warm Looks: simple, one color, minimal stylingFunction: light weight, not durable, little support
Do all the factors have the same importance?(We all know looks matters more than comfort, right?)
Priority• Put the four factors in order from most to
least important.Price, Comfort, Looks, Function
1. _________________ (most important)2. _________________3. _________________4. _________________ (least important)
Weighting the Priorities• You have a total of 10 weights to use. Allocate
the weights based on priority.
1. Looks x 3 2. Price x 33. Comfort x 24. Function x 2
Adds up to 10
____10
Equation to Rate a Shoe
Price: ____
Comfort: ____
Looks: ____
Function: ____
x ____ = ____
x ____ = ____
x ____ = ____
x ____ = ____
+
+
+
Rating: _________
0 to 10 Weight Total
Sample Calculation
Price: 9
Comfort: 6
Looks: 7
Function: 5
x 2 = 18
x 2 = 12
x 4 = 28
x 2 = 10
+
+
+
Rating: 68
0 to 10 Weight Total
SequenceTextWindow.WriteLine("Rate the price:")price = TextWindow.Read()
VS.
price = TextWindow.Read()TextWindow.WriteLine("Rate the price:")
SelectionIf repeat = "y" Then Goto StartEndIf Checks if the user
types in “y”
IterationIf repeat = "y" Then Goto StartEndIf Checks if the user
types in “y”Goes back to beginning and
repeats program
‘top of program codeStart: GraphicsWindow.Draw...
Exit Card1. Write down the equation you used to rate a
shoe.2. Write example sets of inputs for two shoes
and calculate the rating.3. Describe the relationship between the input
variables.a) How does each affect the rating? b) Compare one variable’s effect to another.