Perl 101 (part 6) - The Perl Toolbox - Math Class (Page 8 of 8 )
And finally, Perl also comes with a set of math functions that allow you to carry out complex mathematical operations. You probably won't need these, but you should at least know of their existence.
Sine of a angle:
sin($radians)Cosine of a angle:
cos($radians)Square root of a number:
sqrt($variable)Exponent of a number:
exp($variable)Natural logarithm of a number:
log($variable)Absolute value of a number:
abs($variable)Decimal value of a number from hexadecimal:
hex($variable)Decimal value of a number from octal:
oct($variable)Integer portion of a number:
int($variable)And here's an example that demonstrates all these:
#!/usr/bin/perl
# set up the choices
print "Pick from the choices below:\n";
print "Sine of an angle[1]\n";
print "Cosine of an angle[2]\n";
print "Square root of a number[3]\n";
print "Exponent of a number[4]\n";
print "Natural logarithm of a number[5]\n";
print "Absolute value of a number[6]\n";
print "Decimal value of a number from hexadecimal[7]\n";
print "Decimal value of a number from octal[8]\n";
print "Integer value[9]\n";
chomp($choice = );
# and process them
if ($choice == 1 || $choice == 2)
{
print "Enter the angle in radians: ";
chomp($angle = );
if($choice == 1)
{
$value = sin($angle);
print("Sine of $angle is $value\n");
}
else
{
$value = cos($angle);
print("Cosine of $angle is $value\n");
}
}
elsif($choice == 3)
{
print "Enter a positive number: ";
chomp($number = );
$value = sqrt($number);
print("The square root of $number is $value\n");
}
elsif($choice == 4)
{
print "Enter a number: ";
chomp($number = );
$value = exp($number);
print("e ** $number = $value\n");
}
elsif($choice == 5)
{
print "Enter a number: ";
chomp($number = );
$value = log($number);
print("The natural log of $number is $value\n");
}
elsif($choice == 6)
{
print "Enter a number: ";
chomp($number = );
$value = abs($number);
print("The absolute value of $number is $value\n");
}
elsif($choice == 7)
{
print "Enter a number: ";
chomp($number = );
$value = hex($number);
print("The decimal value of $number is $value\n");
}
elsif($choice == 8)
{
print "Enter a number: ";
chomp($number = );
$value = oct($number);
print("The decimal value of $number is $value\n");
}
elsif($choice == 9)
{
print "Enter a number: ";
chomp($number = );
$value = int($number);
print("The integer value of $number is $value\n");
}
else
{
print("Invalid choice\n");
}
And finally, if you need to use Perl to generate random numbers, you should know about the rand() function. The rand() function takes a number as parameter, and generates a random number between 0 and that number. Here's an example:
#!/usr/bin/perl
print rand(9);
And this could return
7.06539493566379
If you omit the parameter, you'll get a random number between 0 and 1. And here's a script that asks you for a numerical range, and then returns a random number within that range:
#!/usr/bin/perl
# get the limits
print "Enter the lower limit of the range: ";
$lower = ;
chomp ($lower);
print "Enter the upper limit of the range: ";
$upper = ;
chomp ($upper);
# keep generating until number falls within range
while ($random < $lower)
{
$random = int(rand($upper));
}
# then print
print $random;
And that's about all we have time for today. We'll be back with more in a couple of weeks - so keep coming back!
This article copyright Melonfire 2000. All rights reserved.| DISCLAIMER: The content provided in this article is not warranted or guaranteed by Developer Shed, Inc. The content provided is intended for entertainment and/or educational purposes in order to introduce to the reader key ideas, concepts, and/or product reviews. As such it is incumbent upon the reader to employ real-world tactics for security and implementation of best practices. We are not liable for any negative consequences that may result from implementing any information covered in our articles or tutorials. If this is a hardware review, it is not recommended to open and/or modify your hardware. |
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