Can someone explain me how this code works?

Question

sum = 0
x = 10
while x > 0:
sum += x
x -= 1

print(sum)

Answer 1

In loop “while” - x is decreasing by 1 each iteration from 10 to 1
10, 9, 8, 7, 6, 5, 4, 3, 2, 1
When x becomes 0 - loop quits, as x > 0 is False.
Each iteration sum is increasing +x.
So sum = 0 +10 + 9 + 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1 = 55

Answer 2

Sum =0
Then while loop runs ...with X value 10
So sum =sum+X --->0+10
Then sum =10 now,
After that X become 9 #decremented
So 10+9=19--->sum

Like this it will add ...at last you get 55...as output

Answer 3

Sure Nesar Ahmad Yawari

While loop will fail when the X value become 0 until it become 0 it will be true...
Now you got it..

Answer 4

Nesar Ahmad Yawari here,

Till the while loop is true it will add the X value with sum and X value get decremented till the while loop fails and finally it prints the whole sum value...

Answer 5

Nesar Ahmad Yawari add the X value one by one with sum you get 55 as output...

Answer 6

Hi Riya,
I just got introduced to while loop and I just know what while can do but what is the purpose of sum here? What is sum doing here?
I will be glad if you can write me an answer.

Answer 7

Hi Riya,
So at first 10 minus 1 aquals to 9 because we have sum+=x and then we will minus 10 by 1 till 1 because we have while x > 0: and then we have:
10
9
8
7
6
5
4
3
2
1
And we sum them, right?

Answer 8

Close. 10 minus 1 because x -= 1
Then 10 + 9 because sum += x
Sum will be 55 when finished. 10+9+8+7...1 = 55

Answer 9

The code will add 10 to 1. So
10 + 9 + 8 + 7 ... + 1

sum += x
0 += 10
10 += 9
19 += 8
27 += 7
34 += 6
40 += 5
45 += 4
49 += 3
52 += 2
54 += 1

sum = 55

The sum is the initial value (which is 0). And the purpose of it is to add every x into it.

And think of the *while* loop as a limit or when the *while loop* stops. In your example, x > 0, which means from the value of x until 1 (excluding 0).

Answer 10

Thanks MorpheusGranger

Answer 11

It takes the sum of all integers from 10 to 1 using 1 decrement in a while loop

Answer 12

Thanks a lot saikumat chinna.
Actually the Sololearn community is pretty friendly and helpful.

Answer 13

the loop is going to iterate from 10 to 1 but since the print function is outside while loop the variable 'sum' will be equal to 10+9+8+7+6+5+4+3+2+1, that means the print function will not be looped, so you will have only one output of the sum which is equal to 55

Answer 14

Thanks Daudasaeed,
And good morning Tahirssk Tahirssk.

Answer 15

Hi Riya,
Ok so till the while loop is True it will add 10 which is x value with 0 which is sum and 10 which is x gets decremented till the while loop fails? like how it fails?
I would be glad if you explain a bit more.
Thanks

Answer 16

I see, so thats how it works.
Thanks a lot Riya

Answer 17

Sorry for bothering Riya,
But the result is 55 after I hit debug, can you please explain how it equals to 55?
I will appreciate an answer.

Answer 18

Thanks PythonER.

Answer 19

Engineer X Simple explanation...Thanks

Answer 20

Loops are used to repeatedly execute a block of program statements. The basic loop structure in Python is while loop. Here is the syntax.