Dear all, I'm so confused. Just wrote this extremely basic program in Perl and it does not work in the way I expected it to work. Here is the code: 
    my $range = 0.1;
    my $i = 0;
    while( $i < 1 )
    {
        print $i."\n";
        $i = $i + $range;
    }

[download]
What does it return? 
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1

[download]
Why the "1" at the end? I don't know. But that I can handle. Check out what happens if I want it to loop till $i is lower than 10. The code is now: 
    my $range = 0.1;
    my $i = 0;
    while( $i < 10 )
    {
        print $i."\n";
        $i = $i + $range;
    }

[download]
The result is: 
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
4
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
4.9
5
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.99999999999999
6.09999999999999
6.19999999999999
6.29999999999999
6.39999999999999
6.49999999999999
6.59999999999999
6.69999999999999
6.79999999999999
6.89999999999999
6.99999999999999
7.09999999999999
7.19999999999999
7.29999999999999
7.39999999999999
7.49999999999999
7.59999999999999
7.69999999999999
7.79999999999999
7.89999999999999
7.99999999999999
8.09999999999999
8.19999999999999
8.29999999999999
8.39999999999999
8.49999999999999
8.59999999999999
8.69999999999999
8.79999999999998
8.89999999999998
8.99999999999998
9.09999999999998
9.19999999999998
9.29999999999998
9.39999999999998
9.49999999999998
9.59999999999998
9.69999999999998
9.79999999999998
9.89999999999998
9.99999999999998

[download]
This is crazy!! I had a course on numerical analysis and am aware that if you add very small numbers, some numerical errors can occur. But this? It's like Perl says 2+2 = 3.9999. What the hell? Please tell me what am I doing wrong. I am guessing it's something with types, confusing strings with numericals... All the very best, Wojciech.

In reply to Simple adding numbers by WojciechGajewski

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