if statement inside a for loop not working

Hi all,

Can someone please explain why this code is not working?

for a = 0.1:0.1:5
    if a == 3
        b = 1;
    end
end

Once 'a' becomes 3, 'b' should be assigned a 1. But nothing happens.. Not sure what is going on

Answer 1

[Adam]

The representation of the results of floating point maths is not 100% accurate so you should never do a straight == between a number created via floating point maths and some other number. Always test within a tolerance.

[van4]

Thank you very much. It's a bit strange to think that even though I'm incrementing by exactly 0.1, it is not in fact "exactly 0.1".

[Jos (10584)]

Welcome to the world of computers using a limited amount of bits to represent numbers!

fprintf('%.40f\n', 0.1)

[van4]

point taken :)