为什么Perl中的'print(52-80)* 42'与'print 42 *(52-80)'不同? [英] Why is 'print (52-80)*42' different than 'print 42*(52-80)' in Perl?

问题描述

Perl ::什么是:

Perl:: What is:

1. (52-80)*42
2. 42*(52-80)

回答:

1. -28
2. -1176

为什么?

请乐于解释/证明这一点！

Have fun explaining/justifying this please!

#!/usr/bin/perl
use strict;
print 42*(52-80) , "\n";
print ((52-80)*42) , "\n";
print (52-80)*42 , "\n";
print "\n";
my $i=(52-80)*42;
print $i, "\n";

输出:

> -1176
> -1176-28
> -1176

推荐答案

如果添加 use warnings; 您会得到:

If you add use warnings; you'll get:

print (...) interpreted as function at ./test.pl line 5.
Useless use of a constant in void context at ./test.pl line 5

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