one case can not be initiatated when plotting using switch-case

when running the following code, case n=0.6 can not be implemented.

for n=0.2:0.2:0.8
    switch n
        case 0.2
            h1=plot(1:3,sin(1:3)+n,'-.xr');

          case 0.4
              h2=plot(1:3,sin(1:3)+n,'-.xg');

          case 0.6
              h3=plot(1:3,sin(1:3)+n,'-.xk');

          case 0.8
              h4=plot(1:3,sin(1:3)+n,'-.xb');
      end
        hold on;
    end

however, when I change the range of n from 0.2:0:2:0.8 to 1:4, everthing is Ok! I dont know why ,if anyone can help explain, thanks a lot!

for n=1:4
    switch n
        case 1
            h1=plot(1:3,sin(1:3)+n);
        case 2
            h2=plot(1:3,sin(1:3)+n);

          case 3
              h3=plot(1:3,sin(1:3)+n);

          case 4
              h4=plot(1:3,sin(1:3)+n);
      end
      hold on;
  end
  legend('1','2','3','4')

Answer 1

[per isakson]

!!! floating point arithmetic suffers from rounding errors !!!

See: http://www.mathworks.se/help/matlab/matlab_prog/floating-point-numbers.html

Try: format hex

On my system your example works, but

    for 0.0 : 0.3 : 1

does not

[Lin LI]

thanks a lot, isakson! I modified the code to the following , but it still doesnt work.

for n=0.2:0.2:0.8

aa=fi(n,1,8,3);

tt=hex(aa);

switch tt

case 02

h1=plot(1:3,sin(1:3)+n,'-.xr');

case 03

h2=plot(1:3,sin(1:3)+n,'-.xg');

case 05

h3=plot(1:3,sin(1:3)+n,'-.xk');

case 06

h4=plot(1:3,sin(1:3)+n,'-.xb');

end

hold on;

kkk=3;

end

legend('1','2','3','4')

[Lin LI]

I add ' ' to 02, and now it works.

[Lin LI]

Is that the reason?