add lec04.py 01.01.04 readme

archives/01-introduction-to-computer-science-and-programming/archives/UNIT-01/04-machine-interpretation-of-program/lec04.py

@@ -0,0 +1,102 @@
+
+##x = 0.5
+##epsilon = 0.01
+##low = 0.0
+##high = x
+##ans = (high + low)/2.0
+##while abs(ans**2 - x) >= epsilon and ans <= x:
+##    print 'ans =', ans, 'low =', low, 'high =', high
+##    if ans**2 < x:
+##        low = ans
+##    else:
+##        high = ans
+##    ans = (high + low)/2.0
+##print ans, 'is close to square root of', x
+
+##def withinEpsilon(x, y, epsilon):
+##    """x,y,epsilon ints or floats.  epsilon > 0.0
+##       returns True if x is within epsilon of y"""
+##    return abs(x - y) <= epsilon
+
+##print withinEpsilon(2,3,1)
+##val = withinEpsilon(2,3,0.5)
+##print val
+
+##def f(x):
+##   x = x + 1
+##   print 'x =', x
+##   return x
+##
+##x = 3
+##z = f(x)
+##print 'z =', z
+##print 'x =', x
+
+##def f1(x):
+##   def g():
+##       x = 'abc'
+##   x = x + 1
+##   print 'x =', x
+##   g()
+##   assert False
+##   return x
+
+##x = 3
+##z = f1(x)
+
+##def isEven(i):
+##    """assumes i a positive int
+##       returns True if i is even, otherwise False"""
+##    return i%2 == 0
+
+##def findRoot(pwr, val, epsilon):
+##    """assumes pwr an int; val, epsilon floats
+##       pwr and epsilon > 0
+##       if it exists,
+##          returns a value within epsilon of val**pwr
+##          otherwise returns None"""
+##    assert type(pwr) == int and type(val) == float\
+##           and type(epsilon) == float
+##    assert pwr > 0 and epsilon > 0
+##    if isEven(pwr) and val < 0:
+##          return None
+##    low = -abs(val)
+##    high = max(abs(val), 1.0)
+##    ans = (high + low)/2.0
+##    while not withinEpsilon(ans**pwr, val, epsilon):
+##        #print 'ans =', ans, 'low =', low, 'high =', high
+##        if ans**pwr < val:
+##           low = ans
+##        else:
+##           high = ans
+##        ans = (high + low)/2.0
+##    return ans
+
+##def testFindRoot():
+##    """x float, epsilon float, pwr positive int"""
+##    for x in (-1.0, 1.0, 3456.0):
+##        for pwr in (1, 2, 3):
+##            ans = findRoot(pwr, x, 0.001)
+##            if ans == None:
+##                print 'The answer is imaginary'
+##            else:
+##                print ans, 'to the power', pwr,\
+##                'is close to', x 
+
+#testFindRoot()
+
+##sumDigits = 0
+##for c in str(1952):
+##    sumDigits += int(c)
+##print sumDigits
+
+##x = 100
+##divisors = ()
+##for i in range(1, x):
+##    if x%i == 0:
+##        divisors = divisors + (i,)
+##
+##print divisors
+##print divisors[0] + divisors[1]
+##print divisors[2:4]
+