CODEWITHSUNDEEP
perlfloating-pointdecimal
zephyr0110
zephyr0110

Reputation: 225

Perl weird behaviour in number with decimal point

So I was writing a perl program to do some calculation and I had put a floating point number as

$x = 00.05;

if I print

print $x * 100.0;

It returns 500.0

But if I do

$x = 0.05; print $x * 100.0;

it prints correctly 5.0;

What is this behaviour? Is there any convention I have to obey that I am missing?

Upvotes: 4

Views: 81

Answers (1)

Håkon Hægland
Håkon Hægland

Reputation: 40718

A leading zero means an octal constant, so when you do

my $x = 00.05;

you actually do string concatenation of two octal numbers:

my $x = 00 . 05; # The same as "0" . "5"

which gives you the string "05" and later you do 

print $x * 100.0;  # prints 500

since perl interprets as "05" as the number 5

Upvotes: 10

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