Why the plot code wont work ? check codes below! HELP ME PLEASE

    g=9.81;
            Q = app.Qm3sEditField.Value;
            b = app.bmEditField.Value;
            q = Q/b;
            for j=1:length(q)
                yc=(q(j)^2/g)^(1/3);
                Depth = [0.5*yc 0.6*yc 0.7*yc 0.8*yc 0.9*yc yc 1.1*yc 1.2*yc 1.5*yc 1.9*yc];
                Eprime = [];
                for i=1:length(Depth)
                    E(i,j) = y(i)+q(j)^2/(2*g*y(i)^2);
                    Eprime = [Eprime E(i,j)];
                end
            end
            
                plot(app.UIAxes,Eprime,Depth,'or','MarkerFaceColor','r');
          hold (app.UIAxes,'on')
         
            

[Walter Roberson]

            Q = app.Qm3sEditField.Value;
            b = app.bmEditField.Value;

Do we know for sure that those are not empty? Check their sizes

[poorya gholamnejad]

the size is from -inf to inf !

[Walter Roberson]

Show us the output of

size(Q)
size(b)

[poorya gholamnejad]

I wrote this in script and it worked but i need in appdesigner , why would they be empty ?

[poorya gholamnejad]

[Walter Roberson]

Using your app designer version put a breakpoint in at

q = Q/b;

and show us size(Q) and size(b) there. You will be at the K>> debugging prompt when you do that.