perl - 为什么打印命令在 STDIN 之后执行，尽管在它之前调用？

Question

我有一个简单的程序

use strict;
use warnings;

print "Enter a number:\n";
my $number1 = <STDIN>;
chomp $number1;
print "Enter another number:\n";
my $number2 = <STDIN>;
chomp $number2;
if ( $number2 == 0 ) {
    print "error: cnt divide by zero\n";
}
elsif ( ( $number1 == 0 ) or ( $number2 == 1 )) {
    print "$number1\n";
}
else {
    my $div = $number1 / $number2;
    print "the result is: $div\n";
}

但我不明白为什么打印（输入一个数字并输入另一个数字会显示在 STDIN 之后）。我得到以下输出

[612] perl test.pl
2
0
Enter a number:
Enter another number:
error:cnt divide by zero

Answer 1

$| = 1在程序开始时