# Chapter 8 : Structures¶

### example 8.1 page no :77¶

In [1]:
'''
example 8.1 page no :77
'''

class Point:
def __init__(self):
self.x = 0.0
self.y = 0.0

b = Point()
b.x = 3.0
b.y = 4.0

print b.x , ", " , b.y
distance = b.x * b.x + b.y * b.y
print "Distance : " , distance

3.0 ,  4.0
Distance :  25.0


### example 8.2 page no :79¶

In [2]:
'''
example 8.2 page no :79
'''

class Point:
def __init__(self,x,y):
self.x = x
self.y = y

p1 = Point(3.0, 4.0)
p2 = p1
print p2.x , ", " , p2.y

3.0 ,  4.0


### example 8.3 page no : 80¶

In [3]:
'''
example 8.3 page no : 80
'''

class Point:
def __init__(self,x,y):
self.x = x
self.y = y

def printPoint(p):
print "(" , p.x , ", " , p.y , ")"

p1 = Point(3.0, 4.0)
printPoint(p1)

( 3.0 ,  4.0 )


### example 8.4 page no : 80¶

In [4]:
'''
example 8.4 page no : 80
'''

class Point:
def __init__(self,x,y):
self.x = x
self.y = y

def distance(p1,p2):
dx = p2.x - p1.x
dy = p2.y - p1.y
import math
return math.sqrt(dx*dx + dy*dy)

p1 = Point(3.0, 4.0)
p2 = Point(4.0,5.0)
print distance(p1,p2)

1.41421356237


### example 8.5 page no : 81¶

In [5]:
'''
example 8.5 page no : 81
'''
class Point:
def __init__(self,x,y):
self.x = x
self.y = y

def reflect(p):
temp = p.x
p.x = p.y
p.y = temp

def printPoint(p):
print "(" , p.x , ", " , p.y , ")"

blank = Point(3.0, 4.0)
printPoint (blank)
reflect (blank)
printPoint (blank)

( 3.0 ,  4.0 )
( 4.0 ,  3.0 )


### example 8.6 page no : 84¶

In [6]:
'''
example 8.6 page no : 84
'''

class Point:
def __init__(self,x,y):
self.x = x
self.y = y

class Rectangle:
def __init__(self,p,x,y):
self.corner = p
self.width = x
self.height = y

c = Point(0.0, 0.0)
b = Rectangle( c, 100.0, 200.0 )
b.width += 50.0
print b.height

200.0


### example 8.7 page no : 84¶

In [7]:
'''
example 8.7 page no : 84
'''

class Point:
def __init__(self,x,y):
self.x = x
self.y = y

class Rectangle:
def __init__(self,p,x,y):
self.corner = p
self.width = x
self.height = y

def findCenter(box):
x = box.corner.x + box.width/2
y = box.corner.y + box.height/2
result = Point(x, y)
return result

def printPoint(p):
print "(" , p.x , ", " , p.y , ")"

box = Rectangle( Point(0.0, 0.0), 100, 200)
center = findCenter (box);
printPoint (center);

( 50.0 ,  100.0 )


### example 8.8 page no : 84¶

In [8]:
'''
example 8.8 page no : 84
'''

def swap(x,y):
temp = x[0]
x[0] = y[0]
y[0] = temp

i = [7]
j = [9]
swap (i, j)
print i[0] , j[0]

9 7


### example 8.9 page no : 85¶

In [11]:
'''
example 8.9 page no : 85
'''

# prompt the user for input86
print "Enter an integer: ",
# get input
try:
x = int(raw_input())
print  x
#  check and see if the input statement succeeded
except:
print "That was not an integer."

# print the value we got from the user

print "What is your name? " ,
name = raw_input()
print name

Enter an integer: a
That was not an integer.