in reply to Integer overflow question

if you use bigint; you will have never have to worry. 
#bad
print 2**59, "\n";    #5.76460752303423e+017
print 2**59+1, "\n";  #5.76460752303423e+017

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#good
use bigint;

print 2**59, "\n";   #576460752303423488
print 2**59+1, "\n"; #576460752303423489

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Re^2: Integer overflow question
by waswas-fng (Curate) on Jan 03, 2005 at 00:23 UTC
    Another thing you may want to mention about bigint is that it is slower than incrementing a normal int. This may be a limiting factor in a counter that is used in a very tight loop (requirement that it support very large ints could mean tight loop or long run).


    -Waswas
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Re^2: Integer overflow question
by ikegami (Patriarch) on Jan 02, 2005 at 22:56 UTC

    Someone looking at your example could think that use bigint alters how many digits print outputs, but that would be wrong. Here's a better example:

    {
   $a = 2**59;        # Saved as a limited precision float.
   $b = 2**59 + 1;    # Saved as a limited precision float.
   print($a,    $/);  # Prints "5.76460752303423e+017".
   print($b,    $/);  # Prints "5.76460752303423e+017".
   print($b-$a, $/);  # Prints "0".
}

{
   use bigint;
   $a = 2**59;        # Saved as an unlimited precision int.
   $b = 2**59 + 1;    # Saved as an unlimited precision int.
   print($a,    $/);  # Prints "576460752303423488".
   print($b,    $/);  # Prints "576460752303423489".
   print($b-$a, $/);  # Prints "1".
}

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