plot polygon function error

I want to draw polygon of some data Ki_bounds(:,1) ,Kp_range

I coded polygon function

function polygon( x,y )

function  polygon( x,y )
%UNTITLED4 Summary of this function goes here
%   Detailed explanation goes here
plot(x,y)
axis([-1 1 -1.6 1])

end

then i called it in main

 x=[ Ki_bounds(:,1); flipud(Ki_bounds(:,1))]
 y=[Kp_range; flipud(Kp_range);];
 poly_set= polygon(x,y);

but it gives error

Error using polygon
Too many output arguments.

Answer 1

[David Goodmanson]

Hi msh,

the reason is pretty simple. You are asking for an output from the function, but you have not provided any in its definition.

Had you written

function  z = polygon( x,y )
%UNTITLED4 Summary of this function goes here
%   Detailed explanation goes here
plot(x,y)
axis([-1 1 -1.6 1])
z = (whatever)
end 

then the call would have worked. Or you can leave the function as is and just call it:

polygon(x,y)

[Matt J]

msh jgtu's answer converted to comment:

yes the function works without using z, the problem came when i use poly_set= polygon(x,y)

i want to use the polygon in Math operation so i used polyset this gives the error