Mistake in fft() help (calculation of single-sided spectrum)?

In the fft() help, a single sided spectrum is calculated as follows:

Y = fft(X);
P2 = abs(Y/L);
P1 = P2(1:L/2+1);
P1(2:end-1) = 2*P1(2:end-1);

First question: Regarding line 3. Why is the entry L/2+1 also taken into accout for the single sided spectrum? Shouldn't this value be part of the other side of the spectrum?

Second question: Regarding line 4. Why is the last entry not multiplied by 2 (the end value of the entry is end-1 instead of end)?

Answer 1

[Samatha Aleti]

You may find your answer in the following links:

https://www.mathworks.com/matlabcentral/answers/356376-can-someone-explaing-the-computation-for-double-sided-and-single-sided-spectrum-in-fft-example

https://www.mathworks.com/matlabcentral/answers/166697-plot-single-sided-amplitude-spectrum