关于MATLAB问题

function [mag, angle] = polar_value(x,y)

% POLAR_VALUE Converts (x,y) to (r,theta)

% Function POLAR_VALUE converts an input (x,y)

% value into (r,theta), with theta in degxees.

% It illustrates the use of optional arguments.

% Define variables:

% angle -- Angle indegrees

% msg -- Error message

% mag -- Magnitude

% x -- Input x value

% Y -- Input y value (optional)

% Record of revisions:

% Date Programmer Description of change

% ==== ========== =====================

% 12/16/98 S. J. Chapman Original code

% Check for a legal number of input argnments.

msg = nargchk(1,2,nargin);

error (msg);

% If the y argument is missing, set it to 0.

if nargin < 2

y = 0;

end

% Check for (0,0) input arguments, and print out

% a warning message.

if x == 0 & y == 0

msg = 'Both x and y are zero: tingle is meaningless! ' ;

warning (msg);

end

% Now calculate the magnitude.

mag = sqrt(x.^2 + y.^2);

% If the second output argument is present, calculate

% angle in degrees.

if nargout == 2

angle = atan2 ( y , x ) * 180/pi;

end

把这个程序的默认输入值由y=0改成x=0

if nargin < 2

y = 0;

end

改为

if nargin < 2

x = 0;

end