perl

1 #!usr/local/bin/perl5 -w

2use strict;

3use warnings;

4my $a;

5my $g;

6$a = 12.5;

7$g = 2*12.5*3.14;

8print "$g\n";

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

0mnsdev13:scripts> ls

FASTA.PL fasta.pl

FASTA.out file/

FASTA.pk lianxi.pl

FASTA.pl oekb_xml_download_url.pl

FASTAFASTA.pl oekb_xml_parse_load.pl

FASTa.pl pl

mnsdev13:scripts> perl5FASTA.pl

78.5

mnsdev13:scripts>

2)

1#!usr/local/bin/perl5 -w

2use strict;

3use warnings;

4my $a;

5my $g;

6$@ =12.5;

7chomp($a=<STDIN>);

8 $g = 2*$a*3.14;

9print "$g\n";

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

0mnsdev13:scripts> ls

FASTA.PL fasta.pl

FASTA.out file/

FASTA.pk lianxi.pl

FASTA.pl oekb_xml_download_url.pl

FASTAFASTA.pl oekb_xml_parse_load.pl

FASTa.pl pl

mnsdev13:scripts> perl5FASTA.pl

0

0

mnsdev13:scripts> perl5FASTA.pl

3

18.84

mnsdev13:scripts>

3)

1#!usr/local/bin/perl5 -w

2use strict;

3use warnings;

4my $a;

5my $g;

6chomp($a=<STDIN>);

7if($a<0){

8 $g=0;

9}

10else{

11 $g = 2*$a*3.14;

12 }

13print "$g\n";

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

0mnsdev13:scripts> ls

FASTA.PL fasta.pl

FASTA.out file/

FASTA.pk lianxi.pl

FASTA.pl oekb_xml_download_url.pl

FASTAFASTA.pl oekb_xml_parse_load.pl

FASTa.pl pl

mnsdev13:scripts> perl5FASTA.pl

0

0

mnsdev13:scripts> perl5FASTA.pl

22

138.16

4)

1#!usr/local/bin/perl5 -w

2use strict;

3use warnings;

4my $a;

5my $g;

6my $c;

7$@ =12.5;

8chomp($a=<STDIN>);

9chomp($g=<STDIN>);

10 $c = $a*$g;

11print "$c\n";

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

0mnsdev13:scripts> ls

FASTA.PL fasta.pl

FASTA.out file/

FASTA.pk lianxi.pl

FASTA.pl oekb_xml_download_url.pl

FASTAFASTA.pl oekb_xml_parse_load.pl

FASTa.pl pl

mnsdev13:scripts> perl5FASTA.pl

1

4

4

mnsdev13:scripts>

5)

1#!usr/local/bin/perl5 -w

2use strict;

3use warnings;

4my $a;

5my $g;

6my $c;

7$@ =12.5;

8$a=<STDIN>;

9$g=<STDIN>;

10 $c = $a x $g;

11print "$c";

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

~

0mnsdev13:scripts> ls

FASTA.PL fasta.pl

FASTA.out file/

FASTA.pk lianxi.pl

FASTA.pl oekb_xml_download_url.pl

FASTAFASTA.pl oekb_xml_parse_load.pl

FASTa.pl pl

mnsdev13:scripts> perl5FASTA.pl

r

5

r

r

r

r

r

mnsdev13:scripts> perl5FASTA.pl

perl

3

perl

perl

perl

mnsdev13:scripts>

1) 写一个程序，计算半径为12.5
的圆的周长。

2) 修改上述程序，用户可以在程序运行时输入半径。如果，用户输入12.5，则应得到和上题一样的结果

3) 修改上述程序，当用户输入小于0
的数字时，程序输出的周长为0，而非负数

4) 写一个程序，用户能输入2
个数字（不在同一行）。输出为这两个数的积

5) 写一个程序，用户能输入1
个字符串和一个数字(n)（不在同一行）。输出为，n
行这个字符串

例如，如果用户输入的是“fred”和“3”,则输出为：3
行，每一行均为fred。如果输入为“fred”和“299792”,则输出为299792行，每一行均为fred。