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Circle is a program for students and tutors in higher education. Circle program provide the user with the standard form ( x –x0)^2 + (y-y0)^2 = r^2, radius and centre(x0,y0), once the user input the Constants' values of the circle Equation of the form Ax^2 + Ay^2 + Dx + Ey + F = 0. if r^2 = 0, Circle program point and display that the graph is the single point (x0,y0), and if r^2 < 0 , Circle program point that the equation has no real solutions, thus no graph. However Circle program also does compute and display the reverse method if the user input the radius and centre values, it display both forms of the circle equation

Python, 501 lines
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#On the name of ALLAH and may the blessing and peace of Allah 
#be upon the Messenger of Allah Mohamed Salla Allahu Aliahi Wassalam.
#Author :Fouad Teniou
#Date : 08/10/08
#Version : 2.4

""" Class of an equation of a circle of the form Ax^2 + Ay^2 + Dx + Ey + F = 0 (A !=0)
it represents a circle or a point or has no graph , depending of the radius value. And a class
of an equation for the circle of radius r and centred at point (x0,y0). """

import math

class Circle(object):
    """ Class that represent an equation of  a circle
    with A,D,E,F constants properties """

    def __init__(self, Avalue,Dvalue,Evalue,Fvalue):
        """ Circle construction takes A,D,E,F Constants """
		
	self.__A = float(Avalue)
	self.__D = float(Dvalue)
	self.__E = float(Evalue)
	self.__F = float(Fvalue)

	self._b = chr(253)
	self._a = self._checkSign(self.__A)
	self._d= self._checkSign(self.__D)
	self._e = self._checkSign(self.__E)
	self._f = self._checkSign(self.__F)
	self._g = ((self.__D/self.__A)/2)
	self._g1= self.__D/2
	self._h =((self.__E/self.__A)/2)
	self._h1 = self.__E/2
	self._i = self._checkSign(self._g)
	self._j = self._checkSign(self._h)
	self._k = (-self.__F/self.__A + self._g**2 +self._h**2)
	self._k1= (-self.__F + self._g1**2 +self._h1**2)
	self._l = "%2.2f" % math.sqrt(abs(self._k))
	self._l1 = "%2.2f" % math.sqrt(abs(self._k1))
	self._m = "(x%s%s)%s+(y%s%s)%s = %s" % \
			     (self._i,self._g,self._b,self._j,self._h,self._b,self._k)
	self._m1 = "(x%s%s)%s+(y%s%s)%s = %s" % \
			     (self._i,self._g1,self._b,self._j,self._h1,self._b,self._k1)
	self._n = "(%s,%s)" % (-self._g,-self._h)
	self._n1 = "(%s,%s)" % (-self._g1,-self._h1)
    def __str__(self):
	""" String representation of the circle equation,
	standard form , centre and radius """
		
        try:
	    math.sqrt(self._k)
	    #Circle raises zero degenerate case
	    assert math.sqrt(self._k) != 0,"The graph is the single point %s" % \
		   Circle.centre(self)
	    if self.__A == 0:
			
		return "\n<Equation of a circle : x%s + y%s %s %sx %s %sy %s %s = 0 \
			\n\n%s %35s %25s \n\n%s %22s %24s\n" %\
			(self._b,self._b,self._d,int(self.D),self._e, \
			int(self.E),self._f,int(self.F),
			'Standard form','Centre(x0,y0)','Radius r' \
			self._m1,Circle.centre(self),Circle.radius(self))
	    else:
		return "\n<Equation of a circle : %sx%s + %sy%s %s %sx %s %sy %s %s = 0 \
			\n\n%s %35s %25s \n\n%s %22s %24s\n" %\
			(int(self.A)self._b,int(self.A),self._b,self._d,int(self.D),self._e, \
			int(self.E),self._f,int(self.F),
			'Standard form', 'Centre(x0,y0)','Radius r' \
			self._m,Circle.centre(self),Circle.radius(self))

	#Circle raises Negative number degenerate case
        except ValueError:
		raise ValueError,\
			" r%s < 0 : Degenerate case has no graph" % self._b

    def getA(self):
	""" Get method for A attribute """

	if self.__A != 0:
	    return self.__A
	else:
	    raise ValueError,\
		  " A value should be different than zero "
	
    def setA(self,value):
	""" Set method for A attribute """

	self.__A = value

    def delA(self):
	""" Delete method for A attribute """

	del self.__A

    #Create A property
    A = property(getA,setA,delA,"A constant")
		
    def getD(self):
	""" Get method for D attribute """

	return self.__D
	
    def setD(self,value):
	""" Set method for D attribute """

	self.__D = value

    def delD(self):
	""" Delete method for D attribute """

	del self.__D

    #Create D property
    D = property(getD,setD,delD,"D constant")

    def getE(self):
	""" Get method for E attribute """

	return self.__E
	
    def setE(self,value):
	""" Set method for E attribute """

	self.__E = value

    def delE(self):
	""" Delete method for E attribute """

	del self.__E
	
    #Create E property
    E = property(getE,setE,delE,"E constant")

    def getF(self):
	""" Get method for F attribute """

	return self.__F
	
    def setF(self,value):
	""" Set method for F attribute """

	self.__F = value

    def delF(self):
	""" Delete method for F attribute """

	del self.__F
	
    #Create F property
    F = property(getF,setF,delF,"F constant")

    def _checkSign(self,value):
	""" Utility method to check the values’ signs and return a sign string """

	if value >= 0:
	    return "+"
	else:
	    return ""

    def radius(self):
	""" Compute radius of a circle """

	if self.__A == 1:
	    return self._l1
	else:
	    return self._l

    def centre(self):
	""" Compute centre(x0,y0) of a circle """

	if self.__A == 1:
	    return self._n1
	else:
	    return self._n

class Equation(Circle):
    """Class that represent a radius and the centre of a circle """

    def __init__(self,x,y,radius):
	"""Equation construction takes centre(xValue,yValue
	and radius"""

	self.__x = float(x)
	self.__y = float(y)
	self.__radius = float(radius)

	self._o = chr(253)
	self._p = self.__radius**2
	self._q = self._checkSign(-self.__x)
	self._r = self._checkSign(-self.__y)
	self._s = "(x%s%s)%s + (y%s%s)%s = %s " % \
		   (self._q,-self.__x,self._o,self._r,-self.__y,self._o,self._p)
	self._t = self.__x**2 + self.__y**2 -self._p
	self._u = self._checkSign(self._t)
	self._v = "x%s + y%s %s %sx %s %sy %s %s = 0 " % \
		  (self._o,self._o,self._q,-self.__x*2,self._r,-self.__y*2,self._u,self._t)

    def __str__(self):
	""" String representation of the circle equation, standard form ,centre and radius """

	#Equation raises radius value < 0
	assert self.__radius > 0, "<Radius value should be greater than zero"

	return ( "\n<Equation for the circle of radius (%s)\
		centred at (%s,%s) is : \n\n%s < -- > %s" ) % \
		(self.__radius,self.__x,self.__y,self._s,self._v)

if __name__ == "__main__":

    circle1 = Circle(16,40,16,-7)
    print circle1

    #Though students might use only values of radius and circle
    print radius.circle1()
    print centre.circle1()

    circle2 = Circle(2,24,0,-81)
    print circle2

    del circle2.A
	
    circle2.A = 1
    print circle2

    equation = Equation(2,5,3)
    print equation 
    
    for doc in (Circle.A,Circle.D,Circle.E,Circle.F):
        print doc.__doc__,doc.fget.func_name,doc.fset.func_name,doc.fdel.func_name

########################################################################################

#Version : Python 3.2


#import math

#class Circle(object):
#    """ Class that represent an equation of a circle
#    with A,D,E,F constants properties"""
#
#    def __init__(self,Avalue,Dvalue,Evalue,Fvalue):
#        """ Circle constructor takes A,D,F,E constants """
#        
#        self.__A = float(Avalue)
#        self.__D = float(Dvalue)
#        self.__E = float(Evalue)
#        self.__F = float(Fvalue)
#        
#        self._b = chr(178)
#        self._a = self._checkSign(self.__A)
#        self._d = self._checkSign(self.__D)
#        self._e = self._checkSign(self.__E)
#        self._f = self._checkSign(self.__F)
#        self._g = ((self.__D/self.__A)/2)
#        self._g1 = self.D/2
#        self._h = ((self.__E/self.__A)/2)
#        self._h1 = self.E/2
#        self._i = self._checkSign(self._g)
#        self._j = self._checkSign(self._h)
#        self._k = (-self.__F/self.__A +self._g**2 + self._h**2)
#        self._k1= (-self.__F +self._g1**2 + self._h1**2)
#        self._l = "%2.2f" % math.sqrt(abs(self._k))
#        self._l1= "%2.2f" % math.sqrt(abs(self._k1))
#        self._m = "(x%s%s)%s+(y%s%s)%s = %s" % \
#                  (self._i,self._g,self._b,self._j,self._h,self._b,self._k)
#        self._m1 ="(x%s%s)%s+(y%s%s)%s = %s" % \
#                  (self._i,self._g1,self._b,self._j,self._h1,self._b,self._k1)
#        self._n = "(%s,%s)" % (-self._g,-self._h)
#        self._n1= "(%s,%s)" % (-self._g1,-self._h1)
#
#        
#    def squared(self):
#        self._w =(-self.__F/self.__A +((self.__D/self.__A)/2)**2 + ((self.__E/self.__A)/2)**2)
#        return self._w
#    def standardForm(self):
#        return "(x%s%s)%s+(y%s%s)%s = %s" % \
#                  (self._checkSign(((self.__D/self.__A)/2)),((self.__D/self.__A)/2),chr(178),self._checkSign(((self.__E/self.__A)/2)),((self.__E/self.__A)/2),chr(178),(-self.__F/self.__A +((self.__D/self.__A)/2)**2 + ((self.__E/self.__A)/2)**2))
#        
#    def __str__(self):
#        """ String representation of the circle equation,
#        standard form, centre and radius"""
#        
#        try:
#            math.sqrt(Circle.squared(self))
#
#            #Circle raises zero degenerate case 
#            assert math.sqrt(Circle.squared(self)) != 0,"The graph is the single point %s" % \
#                   Circle.centre(self)
#            if self.__A == 1:
#                
#                return "\n<Equation of a circle : x%s + y%s %s %sx %s %sy %s %s = 0 \
#                        \n\n%s %35s %25s \n\n%s %22s %24s\n" %\
#                        (self._b,self._b,self._d,int(self.D),self._e,\
#                         int(self.E),self._f,int(self.F),
#                        "Standard form","Center(x0,y0)","Radius r",\
#                        self._m1,Circle.centre(self),Circle.radius(self))
#            else:
#                return "\n<Equation of a circle : %sx%s + %sy%s %s %sx %s %sy %s %s = 0 \
#                        \n\n%s %35s %25s \n\n%s %22s %24s\n" %\
#                        (int(self.A),self._b,int(self.A),self._b,self._d,int(self.D),self._e,\
#                         int(self.E),self._f,int(self.F),
#                        "Standard form","Center(x0,y0)","Radius r",\
#                        Circle.standardForm(self),Circle.centre(self),Circle.radius(self))
#                
#        #Circle raises Negative number degenerate case    
#        except ValueError:
#            raise ValueError("r%s < 0 : Degenerate case has no graph" % self._b)  
#            
#    def getA(self):
#        """ Get method for A attribute """
#        if self.__A !=0:
#            return self.__A
#        else:
#            raise ValueError("A value should be differtent than zero")
#       
#    def setA(self,value):
#        """ Set method for A attribute """
#       
#        self.__A = value
#        
#    def delA(self):
#        """Delete method for A attrobute"""
#        
#        del self.__A
#
#    #Create a property
#    A = property(getA,setA,delA,"A constant")
#
#    def getD(self):
#        """ Get method for D attribute """
#
#        return self.__D
#
#    def setD(self,value):
#        """ Set method for D attribute """
#        
#        self.__D = value
#        
#    def delD(self):
#        """Delete method for D attrobute"""
#        del self.__D
#
#    #Create a property
#    D = property(getD,setD,delD,"D constant")

#    def getE(self):
#        """ Get method for E attribute """
#        return self.__E
#
#    def setE(self,value):
#        """ Set method for E attribute """
#        
#        self.__E = value
#        
#    def delE(self):
#        """Delete method for E attrobute"""
#
#        del self.__E
#
#    #Create a property
#    E = property(getE,setE,delE,"E constant")
#
#    def getF(self):
#        """ Get method for F attribute """
#
#        return self.__F
#
#    def setF(self,value):
#        """ Set method for F attribute """
#        
#        self.__F = value
#        
#    def delF(self):
#        """Delete method for F attrobute"""
#
#        del self.__F
#
#    #Create a property
#    F = property(getF,setF,delF,"F constant")
#    
#    def _checkSign(self,value):
#        """ Utility method to check the values's sign
#        and return a sign string"""
#        
#        if value >= 0:
#            return "+"
#        else :
#            return ""
#        
#    def radius(self):
#        """ Computes radius of a circle """
#        if self.__A ==1:
#            return self._l1
#        else:
#            return "%2.2f" % math.sqrt(abs(Circle.squared(self)))
#        
#    def centre(self):
#        """ Computes centre(x0,y0) of a circle """
#        if self.__A == 1:
#            return self._n1
#        else:
#            return "(%s,%s)" % (-((self.__D/self.__A)/2),-((self.__E/self.__A)/2))
#        
#    
#
#class Equation(Circle):
#    """ class that represent a radius and the centre of a circle """
#
#    def __init__(self,x,y,radius):
#        """ Equation construction takes centre(xValue,yValue)
#        and radius """
#
#        self.__x = float(x)
#        self.__y = float(y)
#        self.__radius = float(radius)
#        
#        self._o = chr(178)
#        self._p = self.__radius**2
#        self._q = self._checkSign(-self.__x)
#        self._r = self._checkSign(-self.__y)
#        self._s = "(x%s%s)%s+(y%s%s)%s = %s" % \
#                  (self._q,-self.__x,self._o,self._r,-self.__y,self._o,self._p)
#        self._t = self.__x**2 + self.__y**2 - self._p
#        self._u = self._checkSign(self._t)
#        self._v = "x%s + y%s %s%sx %s%sy %s%s = 0" % \
#                  (self._o,self._o,self._q,-self.__x*2,self._r,-self.__y*2,self._u,self._t)
#    
#    def __str__(self):
#        """ String representation of the circle equation, standard form,
#         centre and radius"""
#        
#        #Equation raises radius value < 0
#        assert self.__radius > 0, "<radius value should be greater than zero"
#
#        return ("\n<Equation for the circle of radius (%s)\
#        centred at(%s,%s) is :\n\n%s <--> %s") %\
#        (self.__radius,self.__x,self.__y,self._s,self._v )     
#    
#        
#if __name__ == "__main__":

#    circle1 =  Circle(10,40,16,-7)
#    print(circle1)
#    
#    print(circle1.radius())
#    print(circle1.centre())
#    circle1.delA
#    circle1.A=1
#    print(circle1)
#    circle3 =  Circle(5,24,0,-81)
#    print(circle3)
#    
#    circle3.E =80
#    print(circle3)
#    
#    equation = Equation(2,5,3)
#    print(equation)
#    
#    
#    for doc in (Circle.A,Circle.D,Circle.E,Circle.F):
#        print(doc.__doc__,"=",doc.fget.__name__,doc.fset.__name__,doc.fdel.__name__)
#######################################################################################

#<Equation of a circle : 10x² + 10y² + 40x + 16y  -7 = 0                         

#Standard form                       Center(x0,y0)                  Radius r 

#(x+2.0)²+(y+0.8)² = 5.34            (-2.0,-0.8)                     2.31

#2.31
#(-2.0,-0.8)

#<Equation of a circle : x² + y² + 40x + 16y  -7 = 0                         

#Standard form                       Center(x0,y0)                  Radius r 

#(x+20.0)²+(y+8.0)² = 471.0           (-20.0,-8.0)                    21.70


#<Equation of a circle : 5x² + 5y² + 24x + 0y  -81 = 0                         

#Standard form                       Center(x0,y0)                  Radius r 

#(x+2.4)²+(y+0.0)² = 21.96            (-2.4,-0.0)                     4.69


#<Equation of a circle : 5x² + 5y² + 24x + 80y  -81 = 0                         

#Standard form                       Center(x0,y0)                  Radius r 

#(x+2.4)²+(y+8.0)² = 85.96            (-2.4,-8.0)                     9.27


#<Equation for the circle of radius (3.0)        centred at(2.0,5.0) is :

#(x-2.0)²+(y-5.0)² = 9.0 <--> x² + y² -4.0x -10.0y +20.0 = 0
#A constant = getA setA delA
#D constant = getD setD delD
#E constant = getE setE delE
#F constant = getF setF delF

4 comments

sebastien.renard 15 years, 6 months ago  # | flag

All the get/set stuff is not very usefull. Use direct access to class members and add a property only if you want to add specific code to handle the member access (get and/or set).

Fouad Teniou (author) 15 years, 6 months ago  # | flag

Thank your comment. However I used the Properties just for that purpose you mentioned, to handle the member access for the Circle equations' constants. It is recommended to use such programming technique for Mathematics equations and scientific programs, for the benefits of the property's set

David Lambert 15 years, 5 months ago  # | flag

(original comments were constricted to 3000 characters)

Point 6 is most important.

2) Too much code! Three abbreviated replacement functions (also with _checkSign) ---

def radius(self):
    """ Compute radius of a circle """

    return (self._l,self._l1)[self.__A==1]

def centre(self):
    """ Compute centre(x0,y0) of a circle """

    return (self._n,self._n1)[self.__A==1]

    #syntax for modern python
    #return self._n1 if self.__A == 1 else self._n

5a) _checkSign is independent of the class, so don't make it a method of the class. Thus, another way to write the Circle constructor is with

def _checkSign(value):
    return '+'[value<0:]

    def float_and_sign(value):
        '''bad activestate.  Align left'''
        return (float(value),_checkSign(value),)

    class Circle(object):
        """ Class that repre...
            bad activestate, insert dedent tokens to align left"""

        def __init__(self, Avalue,Dvalue,Evalue,Fvalue):
            """ Circle construction takes A,D,E,F Constants """

            (self.__A,self._a,) = float_and_sign(Avalue)
            (self.__D,self._d,) = float_and_sign(Dvalue)
            (self.__E,self._e,) = float_and_sign(Evalue)
            (self.__F,self._f,) = float_and_sign(Fvalue)


5b) Inheriting Circle into Equation is a bad plan.  The only thing useful it gets appears to be _checkSign, but we have just moved it into the module namespace, so that's not important.  Worse, class Equations lets us define a circle by center and radius.  It's reasonable to ask for that radius.

    >>> e = Equation(0,0,1)
>>> e.radius()
(I'm guessing attribute error occurs, none of self._l, self._l1 or self.__A are known.)

6) And finally, the property set methods are incorrect. In this example the equation of circle is the same but the standard forms differ. The "set" methods have to recompute all that stuff in the "__init__" method. You could move _g through _n1 computations into a separate method as a function of self, A,D,E and F, which you could then call from __init__, setA, setD, setE, and setF.

>>> circle1 = Circle(16,40,16,-7)
>>> circle1.D = 0
>>> print circle1
<Equation of a circle : 16xý + 16yý + 0x + 16y  -7 = 0          

    Standard form                       Centre(x0,y0)                  Radius r 

    (x+1.25)ý+(y+0.5)ý = 2.25           (-1.25,-0.5)                     1.50

    >>> print Circle(16,0,16,-7)
<Equation of a circle : 16xý + 16yý + 0x + 16y  -7 = 0          

Standard form                       Centre(x0,y0)                  Radius r 

(x+0.0)ý+(y+0.5)ý = 0.6875            (-0.0,-0.5)                     0.83

finally, read the python library code to get some ideas for how python can work.

Fouad Teniou (author) 15 years, 5 months ago  # | flag

I realised that you did run Circle on windows python and this is not for professionals and that is why you thought they were faults in the program, while I can assure you it is running perfectly with no mistakes on DOS. However,I write all my programs for Students and Tutors at the universities and expecting them to be professionals and able to use DOS for windows to run my programs or any other computer language program hint ( The professional way). Regarding the _checkSign Utility method I think your comment does not make sense completely since I learned from a Python professional book how to use Utility methods and the fact that it was the only method that the class inherit, is for others to use the program for other purposes and add methods to suite their needs as may be you are not aware of mathematics of universities level. and python library again is for a non professional people as I realised on your last comment and you could find out yourself my point. 1- start using professional tools ( DOS ) to run the Programs I do write 2- Use professionas resources ( Books ) to learn python 3- Circle is highly superior program only for professional

Created by Fouad Teniou on Wed, 8 Oct 2008 (MIT)
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