An if runs its block once when a condition is true. A while loop runs its block over and over, as long as the condition stays true — rechecking before every pass. It’s how you repeat work without copying and pasting lines.
count = 0
while count < 3:
print(count)
count += 10 1 2
Sometimes you want to stop looping before the condition turns false. A break statement immediately exits the loop, skipping anything left in the current pass.
n = 5
while n > 0:
if n == 3:
break
print(n)
n -= 15 4
i = 0
while i < 3:
i += 1
if i == 2:
continue
print(i)1 3
A while loop can have an else block. It runs once, when the loop finishes because its condition became false — but not if the loop was cut short by a break. That makes else a handy “we finished without stopping early” signal.
x = 0
while x < 2:
print(x)
x += 1
else:
print('Done')0 1 Done
Myth: A while loop stops on its own even if you never change the condition.
Reality: If the condition never becomes false and nothing breaks, you get an infinite loop. Always make sure something inside the loop moves it toward finishing.
Myth: The else block runs when the loop ends by a break.
Reality: It’s the opposite — else runs only when the loop ends normally. A break skips the else.
Watch how the program counter jumps back to the condition check at the end of each iteration, and how a break statement jumps out of the loop entirely:
n = 3
while n > 0:
if n == 1:
break
print(n)
n -= 1
print("Done")What happens if a while loop's condition never becomes False and there is no break statement?
It creates an infinite loop that runs forever until interrupted. — Unlike some bounded loops, a while loop will continuously execute as long as its condition evaluates to True. This results in an infinite loop if unhandled.
What is the purpose of the 'break' statement in a while loop?
To exit the loop immediately, regardless of the condition. — The break statement terminates the loop completely, jumping execution to the first statement after the loop body.
When does the 'else' block of a while loop execute?
When the loop's condition becomes False. — The else block executes only when the while condition is evaluated to False. If the loop is terminated by a break statement, the else block is skipped.
Use a while loop to print the numbers 10, 9, 8, 7, in that order.
Use a while loop that checks if n is greater than 6, and remember to decrement n inside the loop.
n = 10
while n > 6:
print(n)
n -= 1Given `i = 1`, use a while loop to print odd numbers less than 6.
Increment i by 2 in each iteration.
i = 1
while i < 6:
print(i)
i += 2