Extra Practice for Week 1 (Due never)
Code Tracing (CT) and Reasoning Over Code (ROC) Exercises
These problems will help you prepare for hw1 and quiz1. They are
optional and you are encouraged to collaborate when working on them.
Code Tracing (CT)
What will each of these print?
# CT1:
def f(x):
print('f', x)
x += 1
return (x**2) // 10
def g(x):
print('g', x)
x = (7 * x) % 5
return f(x + 3)
x = 5
print(f(g(f(x))) + x)
# CT2:
import math
print(1 * 2 // 1 + 4 - 3)
print(2**4/10 + (3 + 2**3) // 10)
print(round(8/3) + max(8/3, math.ceil(8/3)))
# CT3:
def f(x, y):
if (x > y):
if (x > 2 * y): print('A')
else: print('B')
print('C')
def g(x, y):
if (abs(x % 10 - y % 10) < 2): print('D')
elif (x % 10 > y % 10): print('E')
else:
if (x // 10 == y // 10): print('F')
if (x // y > 0): print('G')
f(3,4)
g(1,2)
# CT4:
def f(x):
return 3 * x - 2
def g(x):
return f(x + 3)
def h(x):
print(f(x - 2))
x -= 2
print(g(x))
x %= 4
return f(g(x) % 6) // 2
print(3 + h(4))
# CT5:
def f(x):
return 2 * x + 1
def g(x):
return f(x // 2)
def h(x):
if (x % 2 == 0):
return f(x + g(x))
else:
return f(x) - g(x)
def ct(x):
print(h(x))
print(h(x + 1))
print(ct(5))
Reasoning Over Code (ROC)
Find values for the parameters so the functons return True:
def rc1(x, y):
return ((100 > x > y > 0) and
(x + y == 10) and
(y // x == x // y - 1))
def rc2(x):
return ((type(x) == int) and
(int(round(x**0.5))**2 == x) and
(x//10 == x%10 + 2))
def rc3(x, y):
return ((type(x) == type(y) == int) and
(100 > x > y > 0) and
(x % 10 == y // 10) and
(y % 10 == x // 10) and
(x - y == 9))
def almostEqual(x, y):
return abs(x - y) < 10**-9
def rc4(n):
if ((not isinstance(n, int)) or (n < 100) or (n > 999)):
return False
a = n % 10
b = n // 10
return (almostEqual(b**0.5, a) and (a + b == 42))
def rc5(x):
assert(type(x) == int)
return ((x % 10 == x // 10 - 1) and (x // 9 * 9 == x))