one problem about rounding issue (but not the round function)

Hi everyone, I encounter one problem in one part of my program. To simpilfy, it's:

A = 1.495:0.1:2.495;

for i = 1:11
    disp(num2str(A(i),'%5.2f'));
end

it shows:

    1.50
    1.60
    1.70
    1.80
    1.90
    2.00
    2.10
    2.20
   →2.29
    2.40
    2.50

In a different machine it shows:

1.50
1.60
1.70
1.80
1.90
2.00
2.10
2.20
2.30
2.40
→2.49

This may be due to "the round function rounds away from zero to the integer with larger magnitude" in this link's sentence： https://ww2.mathworks.cn/help/matlab/ref/round.html?lang=en But I'm not sure. could anyone help me solve this problem, to let the program stably display correct rounding result? Many thanks.

[Lin Yang]

also some information ( https://uk.mathworks.com/matlabcentral/answers/289738-i-have-a-variable-whose-value-i-am-approximating-to-the-nearest-integer-by-using-round-function-but) here may helps.

Answer 1

[Matt J]

Because of floating point errors, the "2.2950" is really 2.294999999999999999999999999999999999999, which rounds to 2.29. Do instead

A = round( 1.495:0.1:2.495  ,2);

or

 disp(num2str(round(  A(i)  ,2) ,'%5.2f'))