%??script?file:?plotsinc.m
%
%??Purpose:?
%????This?program?illustrates?the?use?of?handle?graphics?
%????commands?by?creating?a?plot?of?sinc（x）?from?-3*pi?to
%????3*pi?and?modifying?the?characteristics?of?the?figure
%????axes?and?line?using?the?“set“?function.
%
%??Record?of?revisions:
%??????Date???????Programmer??????????Description?of?change
%??????====???????==========??????????=====================
%????11/22/97????S.?J.?Chapman????????Original?code?
%
%?Define?variables:
%???Hndl?????????--?Handle?of?line
%???x????????????--?Independent?variable
%???y????????????--?sinc（x）

%?Calculate?sinc（x）
x?=?-3*pi:pi/10:3*pi;
y?=?sin（x）?./?x;

%?Find?the?zero?value?and?fix?it?up.??The?zero?is
%?located?in?the?middle?of?the?x?array.
index?=?fix（length（y）/2）?+?1;
y（ind