function val = MonteCarlo(fun,a,b,n,hObject)

handles=guidata(hObject);
t=[a:0.01:b];
f=fun(t);
axes(handles.montecarlo);
plot(t,f,'LineWidth',2);
title('Monte Carlo');
axis tight;
maxV=max(f);
minV=min(f);

k=0;
j=0;
hold on;
for i=1:n
    x=a+(b-a)*rand(1);
    y=minV+(maxV-minV)*rand(1);

    if(y>=0 & y<=fun(x)) k=k+1; plot(x,y,'Color','g','LineWidth',2);
    elseif(y<0 & y>fun(x)) j=j+1; plot(x,y,'Color','g','LineWidth',2);
    else plot(x,y,'Color','r','LineWidth',2);
    end
    val=(k-j)/i*(maxV-minV)*(b-a);
    set(handles.MCval,'String',num2str(val,'%.4f'))


    pause(0.0001);
end
hold off;
val=(k-j)/n*(maxV-minV)*(b-a);
end