I found strange error in matlab R2013a calculation using0 'floor'

Use variable c1=0.011. c1 is multiplied by 10 until c1=11. Then use floor(c1) and get value 10

c1=0.011;
  c1=c1*10;
  c1=c1*10;
  c1=c1*10;
  floor (c1)
  ans =
      10

Then use variable c1=0.0011. c1 is multiplied by 10 until c1=11. Then use floor(c1) and get value 11

c1=0.0011;
c1=c1*10;
c1=c1*10;
c1=c1*10;
c1=c1*10;
 floor (c1)
ans =
    11

Then use variable c1=0.11. c1 is multipled by 10 until c1=11. Then use floor(c1) and get value 11

c1=0.11;
c1=c1*10;
c1=c1*10;
 floor (c1)
ans =
    11

WHY the first result differ from second and third?

Answer 1

[A Jenkins]

Because floating point math is a strange thing.

Try setting

format long

and then rerun your above calculations. (Remove the semicolons so you can the results.)

Also look at the FAQ and the links included there: http://www.mathworks.com/matlabcentral/answers/57444-faq-why-is-0-3-0-2-0-1-not-equal-to-zero