1. Object-Oriented Programming and class DesignPs
Module 6
Object-Oriented Programming and class Design
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CSE 1321 Module 5

2. Class Circle Pseudocode
BEGIN
CREATE Radius ← 1.0
CONSTRUCTOR Circle //called default constructor
BEGIN END CONSTRUCTOR
CONSTRUCTOR Circle (NewRadius) //called constructor
Radius ← NewRadius
END CONSTRUCTOR
METHOD getArea () //compute and return circle area
RETURN (Radius * Radius * )
END METHOD
END CLASS Ps
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3. Python Class Circle import math class Circle:
#construct a circle object
def __init__(self, radius):
self.radius = radius
#get area method
def getArea(self):
return self.radius * self.radius * math.pi 8
4/26/2018
CSE 1321 Module 6

4. Ps Driver in Pseudocode
CLASS TestCircle BEGIN CREATE circle1, circle2 AS Circle // create two variables circle1 ← NEW circle() // create circle1 object circle2 ← NEW circle(25.0) // create circle2 object PRINT ("Circle 1 area = " + circle1.getArea()) PRINT ("Circle 2 area = " + circle2.getArea()) END TestCircle Outputs: Circle 1 area = Circle 2 area = Ps
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CSE 1321 Module 6 5

5. Python Class TestCircle
def main():
#create circle with radius 1
circle1 = Circle(1)
print ('The area of the circle with radius', circle1.radius, 'is', circle1.getArea())
#create circle with radius circle2 = Circle(25)
print ('The area of the circle with radius', circle2.radius, 'is', circle2.getArea())
main() #call to main function
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6. Example
CLASS BMW_Z4 BEGIN CONSTRUCTOR BMW_Z4() // constructor #1 BEGIN ModelYear ← 2004 TopUp ← false LicensePlate ← "DEALER" END CONSTRUCTOR CONSTRUCTOR BMW_Z4(parameter: year) // constructor #2 BEGIN ModelYear ← year TopUp ← false LicensePlate ← "DEALER" END CONSTRUCTOR END CLASS Ps
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7. Python – Overload Constructor Example
Python doesn’t support overloading, but there are ways to work around this. We can still write only one constructor, but create it so that it accept multiple arguments. Then, in the constructor, we can look for certain values and assign them accordingly, as shown below:
#construct a BMW object
def __init__(self, modelYear = 2018, TopUp = True, licensePlate = "DEALER"):
self.modelYear = modelYear
self.topUp = TopUp
self.licensePlate = licensePlate
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8. Properties Example Pseudocode
CLASS BMW_Z4 BEGIN PRIVATE ModelYear PRIVATE LicensePlate PUBLIC METHOD SetModelYear (Year) BEGIN ModelYear ← Year END PUBLIC METHOD GetModelYear () BEGIN RETURN ModelYear END PUBLIC METHOD SetLicensePlate (value) BEGIN LicensePlate ← value END PUBLIC METHOD GetLicensePlate () BEGIN RETURN LicensePlate END END CLASS Ps
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CSE 1321 Module 6 5

9. Class BMW_Z4 class BMW: def setModelYear(self, modelYear):
self.modelYear = modelYear
def getModelYear(self):
return self.modelYear
def setTopUp(self, topUp):
self.topUp = topUp
def getTopUp(self):
return self.topUp
def setLicensePlate(self, licensePlate):
self.licensePlate = licensePlate
def getLicensePlate(self):
return self.licensePlate 8
4/26/2018
CSE 1321 Module 6