If I try this oneliner:

perl -e "$a=-50.123456;for($i=0;$i<20;$i++){print qq!$i $a\n!;$a+=0.01}"

I get this:

0 -50.123456
1 -50.113456
2 -50.103456
3 -50.093456
4 -50.083456
5 -50.073456
6 -50.063456
7 -50.053456
8 -50.043456
9 -50.033456
10 -50.023456
11 -50.013456
12 -50.003456
13 -49.993456
14 -49.983456
15 -49.973456
16 -49.963456
17 -49.953456
18 -49.943456
19 -49.933456

[download]

But if I try this one:

perl -e "$a=-71.123456;for($i=0;$i<20;$i++){print qq!$i $a\n!;$a+=0.01}"

I get this:

0 -71.123456
1 -71.113456
2 -71.103456
3 -71.093456
4 -71.083456
5 -71.073456
6 -71.063456
7 -71.053456
8 -71.043456
9 -71.033456
10 -71.023456
11 -71.0134559999999
12 -71.0034559999999
13 -70.9934559999999
14 -70.9834559999999
15 -70.9734559999999
16 -70.9634559999999
17 -70.9534559999999
18 -70.9434559999999
19 -70.9334559999999

[download]

What's going on here?

Thanks!

In reply to Floating point issue by vitoco

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