I don't understand this problem
Why counter can be equal to 1 i=1 (like in the code below) or can be replaced by i = 0 and the result is the same?
n = 4
sum = 0 # initialize sum
i = 1 # initialize counter
while i <= n:
sum = sum + i
i = i+1 # update counter
print("The sum is", sum)
# with added line numbers
1. while i < n: # modified this for simplicity.
2. sum = sum + i
3. i = i+1 # update counter
4. print("The sum is", sum)
Here is the execution to wrap your head around it.
# L1: i=1 n=4 sum=0
# L2: i=1 n=4 sum=1
# L3: i=2 n=4 sum=1
# L1: check i<n - True, 2 is less than 4
# L2: i=2 n=4 sum=3
# L3: i=3 n=4 sum=3
# L1: check i<n - True, 3 is less than 4
# L2: i=3 n=4 sum=6
# L3: i=4 n=4 sum=6
# L1: check i<n - False, 4 not less than 4 ; its equal. condition fail.
# L4: print 6
In case of starting from 0.
# L1: i=0 n=4 sum=0
# L2: i=0 n=4 sum=0 # see sum is 0+0
# L3: i=1 n=4 sum=0
# L1: check i<n - True, 1 is less than 4
# L2: i=1 n=4 sum=1
# L3: i=2 n=4 sum=1
# L1: check i<n - True, 2 is less than 4
# L2: i=2 n=4 sum=3
# L3: i=3 n=4 sum=3
# L1: check i<n - True, 3 is less than 4
# L2: i=3 n=4 sum=6
# L3: i=4 n=4 sum=6
# L1: check i<n - False, 4 not less than 4 ; its equal. condition fail.
# L4: print 6
When you contrast both; you did an extra iteration of work in the second case. But, that contributes nothing to the sum.
Hope this helps
i=0doesn't add anything to sum.