perl：bignum不能与STDIN一起使用

Question

#!/usr/bin/perl

use bignum;

$line = <STDIN>;
( $arr[0], $arr[1], $n ) = split( / /, $line );
$i = 2;

sub func {
    while ( $i < $n ) {
        $t = $arr[ $i - 1 ];
        $arr[$i] = $arr[ $i - 1 ] * $arr[ $i - 1 ] + $arr[ $i - 2 ];
        $i = $i + 1;
    }
    return $arr[ $i - 1 ];
}

print func;

when i am setting manual value for $arr[1] then bignum is working fine but when the value is taken from STDIN then it is being printed as integer no BIGINt. can anyone explain why this is happening.

Answer 1

When you use strings in a numeric context, perl converts them using your C library's atof() . This is not changed by bignum . If you'd like your strings converted in a different manner, I'd recommend Math::BigFloat->new or Math::BigInt->new .