why is my vector bigger than how I created

I tried to do a remain sum using matlab and graph it,

why is my sumvec vector is 101? should the while loop runs from 10 to 100

%equ = sqrt(x+1)
% calculating remain sum of sqrt(x+1) from with 10 to 100 sub interval
sum = 0
sumvec = []
for n = 10:100
    sum = 0
    width = (3 - 0)/n
    
    for c = 0:n
        base = width * c
        height = sqrt(base+1)
        sum = sum + (width * height)
    end
    sumvec(n+1) = sum
end
figure;
i = 0:101
scatter(i,sumvec)

[Stephen Cobeldick]

"why is my sumvec vector is 101? should the while loop runs from 10 to 100"

When n==100, which element do you expect this indexing to refer to?:

sumvec(n+1) = ..

Important: do NOT call any variable sum, as this shadows the very important inbuilt sum function.

Answer 1

[Bastian Arturo Romero Mardones]

Because the values are saved from space 11 onwards.

You must change n+1 in sumvec()

n+1 = 11 -- n-9 = 1

sum = 0
sumvec = []
for n = 10:100 
    sum = 0;
    width = (3 - 0)/n;
    
    for c = 0:n
        base = width * c;
        height = sqrt(base+1);
        sum = sum + (width * height);
    end
    sumvec(n-9) = sum; %% change n+1 -- n-9
end
figure;
i = 1:length(sumvec) %i vector
scatter(i,sumvec)