个人感觉课后习题单独分出来比较方便，这里有可能的话会多放些例子，ok，go
###Chapter one
- 计算半径为12.5的园的周长，可自行输入，小于0输出为0
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#!/usr/bin/perl
print "Please input a number: ";
$inputNumber = <STDIN>;
$perimeter = $inputNumber * 2 * 3.14;
print "The perimeter is $perimeter\n";
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###Chapter two
- 半径12.5圆，求周长
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#!/usr/bin/perl
use 5.010;
$pi = 3.141592654;
$circ = 2 * $pi * 12.5;
print "The circumference of a circle of radius 12.5 is $circ.\n";
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- 交互算周长
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#!/usr/bin/perl -w
$pi = 3.141592654;
print "What is the radius?\n";
chomp($radius = <STDIN>);
$circ = 2 * $pi * $radius;
print "The circumference of a circlee of radius $radius is $circ.\n";
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- 加验证的交互算周长
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#!/usr/bin/perl
$pi = 3.1415926;
print "What is the radius?";
chomp($radius = <STDIN>);
$circ = 2 * $pi * $radius;
if ($radius < 0){
$circ = 0;
}
print "The circumference of a circle of radius $radius is $circ.\n";
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- 交互求和
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#!/usr/bin/perl
print "Enter first number: ";
chomp($one = <STDIN>);
print "Enter second number: ";
chomp($two = <STDIN>);
$result = $one + $two;
print "The result is $result.\n"
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- 字符串重复术，中间的是小写字母x
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#!/usr/bin/perl
print "Enter a string: ";
$str = <STDIN>;
print "Enter a number of times: ";
chomp($num = <STDIN>);
$result = $str x $num;
print "The result is:\n$result";
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Chapter three
- 将输入的字符串倒序打印
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#!/usr/binj/perl
use 5.010;
print "Enter some lines, then press Ctrl-D:\n";#or try Ctrl-Z
@lines = <STDIN>;
@reverse_lines = reverse @lines;
print "@reverse_lines";
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- 键入数字，输出对应的name
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#!/usr/bin/perl
@names = qw/ guo qiu arvon mo love /;
print "Enter some number from 1 to 5, one per line, then press Ctrl-D:\n";
#print @names;
chomp(@number = <STDIN>);
#print "\@number is @number\n";
foreach $num (@number){
# print "now \$num is $num";
print "$names[ $num -1 ]\n";
}
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- 注释的是在一行输入输入的，没注释的分行显示
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#!/usr/bin/perl
#chomp(@lines = <STDIN>);
#@sorted = sort @lines;
#print "@sorted\n";
print sort <STDIN>;
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###小代码块
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sub max {
if (@_ != 2){
print "WAENING! &max should get exactly two argumnets!\n";
}
# follow
#...
}
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