Exercises

Exercise 1: if versus elif

• What is the difference between an elif and a if just after another if?

x = 4
if x > 3:
  print("Greater than 3")
elif x < 5:
  print("Less than 5")

Greater than 3

x = 4
if x > 3:
  print("Greater than 3")
if x < 5:
  print("Less than 5")

Greater than 3
Less than 5

Exercise 2

import turtle
t = turtle.Turtle()
choice = input("Choose between square, circle or both: ")
if choice.lower() == "square" or choice.lower() == "both":
  turtle.forward(100)
  turtle.right(90)
  turtle.forward(100)
  turtle.right(90)
  turtle.forward(100)
  turtle.right(90)
  turtle.forward(100)
if choice.lower() == "circle" or choice.lower() == "both":
  turtle.circle(50)
print("Finished!")

• Which code chunks will execute:
  • If the user types square?
  • If the user types both?
  • If the user types potato?
• Why are we setting choice.lower() in the comparison?

Exercise 3

• Identify the code chunks and write its fluxogram (note the nested ifs!)

print("Lamp doesn't work!")
ans = input("Is the lamp plugged in? ")
if ans == "yes":
  ans = input("Is the bulb burned out? ")
  if ans == "yes":
    print("Replace bulb!")
  else:
    print("Repair lamp!")
else:
  print("Plug in lamp!")