Perl 101 (part 6) - The Perl Toolbox - Math Class
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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.

>>> More Perl Articles          >>> More By Vikram Vaswani and Harish Kamath, (c) Melonfire