# Recursion and Conditionals - PowerPoint PPT Presentation

1 / 11

Recursion and Conditionals. CS1-08 Chapter 6 Exercises. Exercise 1 – Part 1. Fermat’s Last Theorem says that there are no integers a, b, and c such that: a n  +  b n  =  c n for any values of n greater than 2.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

Recursion and Conditionals

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

## Recursion and Conditionals

CS1-08 Chapter 6 Exercises

### Exercise 1 – Part 1

• Fermat’s Last Theorem says that there are no integers a, b, and c such that:

an + bn = cn

for any values of n greater than 2.

• Write a function named check_fermat that takes four parameters—a, b, c and n—and that checks to see if Fermat’s theorem holds. If n is greater than 2 and it turns out to be true that:

an + bn = cn

• the program should print, “Holy smokes, Fermat was wrong!” Otherwise the program should print, “No, that doesn’t work.”

### Ex. 1 - Part 1 Solution

defcheck_fermat(a, b, c, n):

if a**n + b**n == c**n:

print "Holy smokes, Fermat was wrong!"

else:

print "No, that doesn't work"

### Ex. 1 – Part 2

• Write a function that prompts the user to input values for a, b, c and n, converts them to integers, and uses check_fermat to check whether they violate Fermat’s theorem.

### Exercise 1 – Part 2 Solution

defprompt_fermat():

a = int(raw_input("Please enter value for a.\n"))

b = int(raw_input("Please enter value for b.\n"))

c = int(raw_input("Please enter value for c.\n"))

n = int(raw_input("Please enter value for n.\n"))

check_fermat(a, b, c, n),

print " \n"

print "What does the escape code \"\\n\" do?"

print "This solution is just \'ok\'. Why?"

prompt_fermat()

### Exercise 2

• If you are given three sticks, you may or may not be able to arrange them in a triangle. For example, if one of the sticks is 12 inches long and the other two are one inch long, it is clear that you will not be able to get the short sticks to meet in the middle. For any three lengths, there is a simple test to see if it is possible to form a triangle:

• “If any of the three lengths is greater than the sum of the other two, then you cannot form a triangle. Otherwise, you can.”

### Exercise 2 - Part 1

• Write a function named is_triangle that takes three integers as arguments, and that prints either “Yes” or “No,” depending on whether you can or cannot form a triangle from sticks with the given lengths.

### Exercise 2 – Part 1 Solution

defis_triangle(a, b, c):

if a + b >= c:

print "Yes!"

else:

print "No!"

### Exercise 2 – Part 2

• Write a function that prompts the user to input three stick lengths, converts them to integers, and uses is_triangle to check whether sticks with the given lengths can form a triangle.

### Exercise 2 – Part 2 Solution

defprompt_triangle():

a = int(raw_input("Please enter value for a.\n"))

b = int(raw_input("Please enter value for b.\n"))

c = int(raw_input("Please enter value for c.\n"))

is_triangle(a, b, c)

prompt_triangle()

### Exercise 3

• What does the following program do?

Import from TurtleWorld *

def draw(t, length, n):

if n == 0:

return

angle = 50

fd(t, length*n)

lt(t, angle)

draw(t, length, n-1)

rt(t, 2*angle)

draw(t, length, n-1)

lt(t, angle)

bk(t, length*n)