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5.1 Intro To Loops + While Loops

Intro to Loops

Loops are repeated programs that you can tell a computer to run. The point of loops is to tell a computer to do something again and again until you achieve a goal. This is called iteration.

While Loops

While Loops are loops that do something while a condition is met, and you can code that something to change again and again until the condition is no longer met.

For example:

x = 8
while x < 13:
	print("x is still less than 13")
	x += 1

View code on GitHub.

This loop checks if x is less than 13. If it is, then it prints 'x is still less than 13'. Then, it'll add one to x and repeat the process (check x, print, and add one to x). The loop keeps on going until at one point x is no longer less than 13, but It'll print "x is still less than 13" 5 times because that's how many times the computer ran through the loop

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In the above example, the computer prints when x is 8, 9, 10, 11, and 12. This is why it'll print "x is still less than 13" 5 times

Practice

TV

Pretend you just got a 50 on your test, and your mom says you can't watch TV until you get above an 80. (HINT: use comparison operators). You increase your test score by 10 points per day (iterations). Write a program that tells you how many days you're going to need before you can watch TV.

Up 2 Fifty

Write a program that takes a number from the user and adds 2 to it until it reaches 50 or more, then prints out how many times 2 was added. If the number is already greater than 50, then print out "Already there!"

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