How To Write A PERL Program

Perl can basically call any of the system functions and is an interface between the users and any program that the server can run via the program you write.

One ability perl has, like any other computer function is to handle math functions. Basic adding and subtracting to trig and complex math equations.

Lets say we want to add 2 numbers,10 and 15.

Using a varriable just like in algebra, we write:

$numbersadded = (10 + 15);

Then we tell the program to print the answer.

print "$numbersadded";

#!/usr/bin/perl
print "Content-type: text/html\n\n";
$numbersadded = (10 + 15);
print "$numbersadded";

When we access out test program with the browser, it will simply show "25".

This is very useful when we want to add up the cost of items in a shopping cart or make some calculation that will determine the next step the the program. For example if the total shopping cart order is not greater than 0, you wont allow the person to go to the checkout.

The basics are very basic, but it is these basic functions that add up to become very complex programs that run banking systems and huge businesses and databases.

Most e-commerce programs will never require knowing more than addition, subtraction, multiplication and division. There is no need to study all of the math functions unless you are writing software for engineering applications.

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