CS9

🔁 while loops

December 21, 2016

Do Now

# what do you think this will do?
n=1
while n>0:
  print n
  n = n+1

bad stuff infinite loop! 1

✍ while Loop

Code that repeats while a condition is true.

x=1
while x in range(0,4):
  print x
  x = x+1

Let’s take a closer look:

n=1 # sets n to 1. What happens if we don't?
while n>0:
 print(n)
 n = n+1
# Predict!
while True:
  print("whoa")
# What about this? What gives?
while x<5:
  print(x)
  x = x + 1

meanwhile…

In 🐍 CS9 Python:

It takes any number as input, starts counting down and ends with a BOOM! (or similar exclamation.)

It should look like this:

Enter number: 10
10
9
8
7
6
5
4
3
2
1
BOOM!

  1. 🎉 Congratulations! You now have the power to crash Google Chrome. ↩

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