Summing elements within an eval statement, in a for loop

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.

Answer 1

[Geoff Hayes]

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?

[asldkfj]

Edited: N is even. Geoff, I am really on the verge of completing my project, and I have used eval statements everywhere, so I am trying to use that here. I will keep the array concept in mind for next time.

[Walter Roberson]

If I were marking, I would deduct marks for using eval() unless the student could convince me there was no other way.