MATLAB: Summing elements within an eval statement, in a for loop

evalfor loopnum2str

I have written a complete code that runs in MATLAB, but outputs a slightly incorrect result. I need to get the following:
utotal
where
utotal = S1plot + S2plot + ...
until the digit equals (N/2) + 1, where N is even. If N = 10, say, the digit would be 6.
Then I need to evaluate utotal within the script. How can I achieve this?
This is what I have so far:
    N = 10;
    for alpha = 1:(N/2+1)
        eval(['utotal = sum(S' num2str(alpha) 'plot);'])
    end
but it doesn't work because it evaluates the following:
    u1 = sum(S1plot);
    u1 = sum(S2plot);
    u1 = sum(S3plot);
    u1 = sum(S4plot);
    u1 = sum(S5plot);
    u1 = sum(S6plot);
Thanks in advance for help.

Best Answer

Abhi - since you are summing elements on each iteration of a for loop, you would need to do something like
 N = 10;
 utotal = 0;
 for alpha = 1:(N/2+1)
     utotal = utotal + ...;
 end
Use of eval is strongly discouraged as you have noticed with problems in your code. Why are you creating all of the different variables named SXPlot? Why not just create an array for all of these value?
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