Chapter 14 : Classes and invariants

example 14.1 page no :149

In [1]:
'''
example 14.1 page no :149
'''

class Card:
    def __init__(self,s=None,r=None):
        if s==None:
            self.suit = 0
            self.rank = 0
        else:
            self.suit = s; 
            self.rank = r;

    def getRank (self):
        return self.rank
        
    def getSuit (self):
        return self.suit
    
    def setRank(self,r):
        self.rank = r        

    def setSuit (self, s):
        self.suit = s

example 14.2 page no :151

In [2]:
'''
example 14.2 page no :151
defining class 
'''

class Complex:
    def __init__(self,r=None,i=None):
        if r==None:
            pass
        else:
            self.real = r
            self.imag = i

example 14.3 page no : 152

In [3]:
'''
example 14.3 page no : 152
'''
import math
class Complex:
    def __init__(self,r=None,i=None):
        if r==None:
            self.real = 0
            self.imag = 0
            self.polar = False
            self.cartesian = False
        else:
            self.real = r
            self.imag = i
            self.cartesian = True
            self.polar = True
        self.mag = 0
        self.theta = 0

    def getReal (self):
        if (self.cartesian == False):
            self.calculateCartesian ();
        return self.real;
        
    def getImag(self):
        return self.imag

    def calculateCartesian (self):
        self.real = self.mag * math.cos(self.theta);
        self.imag = self.mag * math.sin (self.theta);   
        self.cartesian = True;

    def printCartesian (self):
        print self.getReal() , " + " , self.getImag() , "i"

    def printPolar(self):
        print self.mag , " e^ " , self.theta , "i"


c1 = Complex(2.0, 3.0);
c1.printCartesian();
c1.printPolar();

2.0  +  3.0 i
0  e^  0 i

example 14.4 page no : 155

In [4]:
'''
example 14.4 page no : 155
'''
class Complex:
    def __init__(self,r=None,i=None):
        if r==None:
            self.real = 0
            self.imag = 0
            self.polar = False
            self.cartesian = False
        else:
            self.real = r
            self.imag = i
            self.cartesian = True
            self.polar = True
        self.mag = 0
        self.theta = 0
        
    def getReal (self):
        if (self.cartesian == False):
            self.calculateCartesian ();
        return self.real;
        
    def getImag(self):
        return self.imag


    def add(self,b):
        real = self.getReal() + b.getReal();
        imag = self.getImag() + b.getImag();
        s = Complex(real, imag);
        return s

    def printCartesian (self):
        print self.getReal() , " + " , self.getImag() , "i"

c1 = Complex(2.0, 3.0);
c2 = Complex(3.0, 4.0);
s = c1.add (c2);
s.printCartesian();

5.0  +  7.0 i

example 14.5 page no :156

In [8]:
'''
example 14.5 page no :156
'''
import math
class Complex:
    def __init__(self,r=None,i=None):
        if r==None:
            self.real = 0
            self.imag = 0
            self.polar = False
            self.cartesian = False
        else:
            self.real = r
            self.imag = i
            self.cartesian = True
            self.polar = True
        self.mag = 0
        self.theta = 0
        
    def getReal (self):
        if (self.cartesian == False):
            self.calculateCartesian ();
        return self.real;
        
    def getImag(self):
        return self.imag

    def calculateCartesian (self):
        self.real = self.mag * math.cos(self.theta);
        self.imag = self.mag * math.sin (self.theta);   
        self.cartesian = True;


    def printCartesian (self):
        print self.getReal() , " + " , self.getImag() , "i"

    def mult(self,b):
        mag = self.mag * b.mag
        theta = self.theta + b.theta
        product = Complex()
        product.setPolar (mag, theta);
        return product;

    def setPolar(self,m,t):
        self.mag = m
        self.theta = t;
        self.cartesian = False
        self.polar = True;

example 14.6 page no :159

In [9]:
'''
example 14.6 page no :159
defining class Complex
'''

class Complex:
    def __init__(self,r=None,i=None):
        if r==None:
            self.real = 0
            self.imag = 0
            self.polar = False
            self.cartesian = False
        else:
            self.real = r
            self.imag = i
            self.cartesian = True
            self.polar = True
        self.mag = 0
        self.theta = 0
        
    def getReal (self):
        if (self.cartesian == False):
            self.calculateCartesian ();
        return self.real;
        
    def getImag(self):
        return self.imag

    def printCartesian (self):
        print self.getReal() , " + " , self.getImag() , "i"

    def mult(self,b):
        mag = self.mag * b.mag
        theta = a.theta + b.theta
        product = Complex()
        product.setPolar (mag, theta);
        return product;

    def setPolar(self,m,t):
        self.mag = m
        self.theta = t;
        self.cartesian = False
        self.polar = true;
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