% 求最大數(shù)
 x=1;
 while x~=inf;
     x1=x;
     x=2*x;
 end
 x1

 %求相對(duì)精度eps
 
y=1;
while y~=0
    y1=y;y=y/2;
end
y1
 format long
 y1 
 format short
 
 %求相對(duì)精度eps
y=1;
while 1+y>1,
    y2=y;y=y/2;
end
y2
 format long 
 y2
 format short