MATLAB: Undefined function or variable “Horz_average_l”

Question

I read many answers for question: Undefined function or variable in forum, and check with my code, but i have not repaired that error. Can u see to help me?

function[Horz_average_l,Horz_average_r]= Horz_avg(Start,End,side) Sum =0; ITERATIONS = 200;

syms i j side Start End

switch side case 1

    for j=0: (ITERATIONS-1),
        for i=Start(j): (Start(j)+End(j))/2-1
            Sum = Sum + BWPic(i,j); 
        end
        Horz_average_l(j)= Sum/((End(j) - Start(j))/2); %Left side only */ 
        Sum = 0; 
    end
case 2
    for j=0:(ITERATIONS-1) 
        for i=((Start(j)+End(j))/2) : (End(j)-1)
        i = i +1;
        Sum = Sum + BWPic(i,j); 
        end 
        Horz_average_r(j)= Sum/((End(j) - Start(j))/2); % Right side only
        Sum = 0; 
    end
end
for j = 0 : (ITERATIONS-4)
    if  Horz_average_l(j+1) >=Horz_average_l(j) && Horz_average_l(j+2) < Horz_average_l(j+1) && Horz_average_l(j+3) >= Horz_average_l(j+2)
end
end

error in the last if

Undefined function or variable "Horz_average_l".

Answer 1

The last if seems to have no body.

Please format all your code.

Why do you use

syms i j side Start End

Where is PWPic defined?

And what is the function exactly supposed to do?