小编Ben*_*man的帖子

我参加了一个Bioinformatics课程,并且我继续在ReverseComp.txt第4行调用"Undefined subroutine&main :: Print".错误

# ReverseComp.txt => takes DNA sequence from user
# and returns the reverse complement

print ("please input DNA sequence:\n");
$DNA =<STDIN>;

$DNA =~tr/ATGC/TACG/;   # Find complement of DNA sequence

$DNA =~reverse ($DNA);  # Reverse DNA sequence

print ("Reverse complement of sequence is:\n");

print $DNA."\n";

这是我的代码,我用第4行尝试了一些不同的东西,但没有结果.有什么建议？(我是在提示中写的,一切看起来都正确......)