#!/usr/bin/python
from random import *

#define a few functions

def IsPalindrome(a):
   length = len(a)
   start = 0
   end = length-1
   while start < length/2:
      if a[start] != a[end]:
         return False
      start += 1
      end -= 1;
   return True

def TestWord (word):
    if IsPalindrome(word):
       print word, " is a palindrome"
    else:
       print word, " is not a palindrome"

# the main program begins here.

# a simple greeting
print("Hello World")
print

# print some letters
for letter in "abcdefg":
   print letter

print

# print some numbers
i = 0;
while (i < 10) :
    print (i)
    i += 1

print

# can we do a conversion to binary
num = 35
value = ""
while num > 1:
   value = str(num % 2) + value
   num = num / 2


if num == 1:
   value = str(num) + value
   
print "35 = ", value
print

# call some functions
TestWord("racecar")
TestWord("abba")
TestWord("able was I ere I saw elba")
TestWord("bad")
print

# strings
print 'hello is "hi" in other places'
print "but 'hi' is also hello sometimes"
print "\tAnd all of the \a's and whistles work too \n\n\t\t\tSee!"
print

print "Cooking a bit of pi"
TRIALS = 100000
hits = 0
i = 0
while i < TRIALS: 
    x = uniform(0,1)
    y = uniform(0,1)
    if x*x + y*y < 1.0:
       hits += 1
    i+= 1
print "pi is about  ", 4.0*float(hits)/float(TRIALS)

print
print "Or Pi from my hero Leibniz"
i = 3
pi = 1.0
sign =  -1.0
while i < TRIALS:
   pi += sign * 1.0/float(i)
   i += 2
   sign *= -1

print 4.0*pi


# a range:
print range(10)
print range(1,10)
print range(1,10,3)

# another pi compuatation
pi = 1
sign =  -1.0
for i in range(3,TRIALS,2): 
   pi += sign * 1.0/float(i)
   sign *= -1

print 4.0*pi