MATLAB: One case can not be initiatated when plotting using switch-case

faqswitch case plot

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')

Best Answer

!!! 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
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