If someone should be blamed for this, it is not Perl, but c, and Perl just inherits it. If you are using languages support fixed decimal, for example COBOL or PL/SQL, then this problem disappears.

Here is an example what can happen to c: (It does not give 14720)

#include <stdio.h>

void main() {
    float x = 147.2;
    printf("%20.20f", x * 100);
}

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If you really care the accuracy and precision, try Math::BigFloat.

Now here is something a little bit off topic, but interesting. If you do this in c:

float x = 147.2;
printf("%d", x * 100);

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It produces -167772160, which is ridiculous, as c tries to interprete that piece of memory as integer, as you required.

Good you are using Perl. In Perl, if you do the same thing with: 

$x = 147.2;
printf("%d", $x * 100);

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It produces 14719 (not precise, but better than c), as internally Perl does: 

float x = 147.2;
printf("%d", (int)(x * 100));

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In reply to Re: (s)printf and rounding woes by pg
in thread (s)printf and rounding woes by Not_a_Number

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