The document discusses different types of loops that can be used when a program needs to repeatedly perform the same actions. It describes while loops, do-while loops, and for loops as well as examples of their uses. Loops allow code to be reused and reduce the number of statements needed compared to writing out repetitive tasks individually. Debugging techniques for loops, like using counters, are also covered.

2. • An application sometimes needs to perform
repetitive actions like:
 Summing Numbers(Averages)
 Entering Multiple Data Entries
 Prompting the User Till the Correct Value is Entered
 A shopping list(scanning through the shopping list and
getting the items 1 by one until the list is down and
then you leave)

3. • When a program repeatedly runs a set of
statements it is referred to as a loop, iteration
or repetition structure.
• There are several types of looping structures:
 While Loops
 Do-While Loops
 For Loops
Counter Controlled Loops
Condional Loops

4. • Loops are similar to conditionals because they run
on a true/false value set. The loop continuously
runs while the condition is true and terminates
when it is false.
• Loops can be run for a desired length or until a
flag terminates them
 Great technique to reuse code and therefore limit
the amount of statements a program needs. Reusing
the same conditional arguments for testing instead
of posting hundreds.
True
False

5.  Question: How many statements are needed
for the following?
 Ask the same question 100 times
 Store the answer in a variable
 Check whether the answer is one of two answers
 Question: How many statements are needed if
we loop the code?

6. • A While Loop is a loop that executes 0 or more times
before terminating.
• Pre-conditional loop
 Code:
 Creating a While Loop:
 while (condition statement):
statement1
statement2
 Debugging Techniques:
 Setup a counter to keep track of the number of times a loop runs
 Set up a counter to count if an event is occurring or the number
of times it occurs
 Output values each time a loop executes

7. num = eval(input(“Enter a number less than 10:”))
while (number >= 10):
print(“Invalid Entry!”)
num = eval(input(“Enter a number less than 10:”))

8.  Counter: a variable that is incremented or
decremented each time a loop repeats
 Can be used to control execution of the loop
(also known as the loop control variable)
 Must be initialized before entering loop