What is the output of this code ?

Question

Hello everyone, i would be needing help to understand this one.

def func(x):
res = 0
for i in range(x):
res += i
return res

print(func(4))

I don't understand how this code works.

Answer 1

for in range means that the looping starts from 0 to n-1. Since the starting value is not given, it is 0 by default and only one parameter is passed which is taken as the limit.

0 in range 4 //true so res=0+0=0
1 in range 4 //true so res=0+1=1
2 in range 4 //true so res=1+2=3
3 in range 4 //true so res=3+3=6
4 in range 4 //false & loop terminates.

So the returned value is 6 and is printed.

Answer 2

Thanks for responding.

I understand your logic but when i execute the code the output is like this :

0 in range 4 // func(0) = 0
1 in range 4 // func(1) = 0
2 in range 4 // func(2) = 1
3 in range 4 // func(3) = 3
4 in range 4 // func(4) = 6