Matlab - como puedo hacer la interfaz de este codigo Matlab

clear all;

clc;

syms x

fx=input('F(x)= ');

gx=input('G(x)= ');

a=input('LI= ');

b=input('LS= ');

c=fx-gx;

h1=gx-fx;

d=0;

k=1;

for i=a:.1:b

    y=subs(c,i);

    if y==0

        disp(i)

        yl2(k)=i;

        d=d+1;

        k=k+1;

    end

end

k=k-1;

t=1;

for j=1:1:k

    xo=j+0.1;

    fxe=subs(fx,xo);

    yf(t)=fxe;

    t=t+1;

end

t2=1;

for j2=1:1:k

    xo2=j2+0.1;

    gxe=subs(gx,xo2);

    yf2(t2)=gxe;

    t2=t2+1;

end

l=k-1;

if k<3

 if yf(l)>yf2(l)

    r=int(c,a,b);

 else

     r=int(h1,a,b);

 end

elseif k==3

    v=k-l;

        c1=yl2(1);

        c2=yl2(2);

        c3=yl2(3);

        if yf(v)>yf2(v)

        r1=int(c,c1,c2);

        r2=int(h1,c2,c3);

        r=r1+r2;

        else

        r1=int(h1,c1,c2);

        r2=int(c,c2,c3);

        r=r1+r2;

        end

end

 r12=abs(r);

 disp('El area entre las curvas es: ')

 disp(r12)

 fxq=str2func(['@(x)' char(fx)]);

 gxq=str2func(['@(x)' char(gx)]);

 px=[];

 py=[];

 for al=a:0.1:b

     px(end+1)=al;

     py(end+1)=gxq(al);

 end

 for al=b:-0.1:a

     px(end+1)=al;

     py(end+1)=fxq(al);

 end

 m=a-1;

 n=b+1;

 ezplot(fx,[m n])

 title('Area entre dos curvas')

 hold on

 grid on

 ezplot(gx,[m n])

 legend('F(x)','G(x)')

 fill(px,py,'c')

este codigo lo agregue a un push vutton pero me da error

% --- Executes on button press in cl.

function cl_Callback(hObject, eventdata, handles)

syms x

fx=get(handles.fxz,'string');

gx=get(handles.gxz,'string');

a=str2double(get(handles.az,'string'));

b=str2double(get(handles.bz,'string'));

c=fx-gx;

h1=gx-fx;

d=0;

k=1;

for i=a:1:b

    y=subs(c,i);

    if y==0

        yl2(k)=i;

        d=d+1;

        k=k+1;

    end

end

k=k-1;

t=1;

for j=1:1:k

    xo=j+0.1;

    fxe=subs(fx,xo);

    yf(t)=fxe;

    t=t+1;

end

t2=1;

for j2=1:1:k

    xo2=j2+0.1;

    gxe=subs(gx,xo2);

    yf2(t2)=gxe;

    t2=t2+1;

end

l=k-1;

if k<3

    if yf(l)>yf2(l)

        rlr=int(c,x);

        rlr1=subs(rlr,b);

        rlr2=subs(rlr,a);

        r=rlr1-rlr2;

    else

        rlr=int(h1,x);

        rlr1=subs(rlr,b);

        rlr2=subs(rlr,a);

        r=rlr1-rlr2;

    end

elseif k==3

    v=k-l;

    c1=yl2(1);

    c2=yl2(2);

    c3=yl2(3);

    if yf(l)>yf2(l)

        r1=int(c,x);

        rlr1=subs(r1,c2);

        rlr2=subs(r1,c1);

        rsr1=rlr1-rlr2;

        r2=int(hl,x);

        rfr1=subs(r2,c3);

        rfr2=subs(r2,c2);

        rsr2=rfr1-rfr2;

        r=rsr1+rsr2;

    else

        r1=int(h1,x);

        rlr1=subs(r1,c2);

        rlr2=subs(r1,c1);

        rsr1=rlr1-rlr2;

        r2=int(c,x);

        rfr1=subs(r2,c3);

        rfr2=subs(r2,c2);

        rsr2=rfr1-rfr2;

        r=rsr1+rsr2;

    end

end

r12=abs(r);

set(handles.res,'string',char(r12));