[akash_9105]

Write a program, which uses post-test loop, to compute the sum of a series of numbers entered by the user. Note that the sum is displayed when the user enters the value 0, i.e. zero

Here is what i have done :

i=0
sum=0.0
x=input("Enter a number : ")

while x!=0:
	sum=x+sum
	x=input("Enter a number : ")
	i=i+1
	
	if x==0:
		print "sum is : ",sum

The code works fine but i am not being able to understand what is meant by a POST TEST LOOP . Can someone explain to me what is meant by a post test loop ?

thanx

[Tshiknn]

A normal loop checks the conditional, then if found true, runs the code. Then it goes back to the conditional and repeats. A post-test loop is a loop that runs the code, then checks the condition, then if found true, runs the code again. The difference is that a post-test loop is always runs the code once, even if the conditional isn't true, whereas a pre-test loop doesn't run the code if the conditional isn't true. Here's the basic form for a post-test loop:

# post-test loop
while True:
	<statements>
	if not <conditional>:
		break

# pre-test loop
while <conditional>:
	<statements>

You don't often use post-test loops, but sometimes they're useful.

[akash_9105]

Thanx for your quick response, so even though my code is working, is it a post test loop ?

Here is my code:

i=0
sum=0.0
x=input("Enter a number : ")

while x!=0:
	sum=x+sum
	x=input("Enter a number : ")
	i=i+1
   
	if x==0:
		print "sum is : ",sum

Tshiknn, on 24 Oct, 2009 - 07:06 PM, said:

A normal loop checks the conditional, then if found true, runs the code. Then it goes back to the conditional and repeats. A post-test loop is a loop that runs the code, then checks the condition, then if found true, runs the code again. The difference is that a post-test loop is always runs the code once, even if the conditional isn't true, whereas a pre-test loop doesn't run the code if the conditional isn't true. Here's the basic form for a post-test loop:

# post-test loop
while True:
	<statements>
	if not <conditional>:
		break

# pre-test loop
while <conditional>:
	<statements>

You don't often use post-test loops, but sometimes they're useful.

[Tshiknn]

No, not really. A post test loop would be an infinite loop that runs the code, then breaks if the conditional isn't true. A post-test loop would look like this in your program:

i=0
sum=0.0
x=input("Enter a number : ")

while True:
	sum=x+sum
	x=input("Enter a number : ")
	i=i+1
   
	if x==0:
		print "sum is : ", sum
		break