Cross Ref > Language Basics

Java is case sensitive.

Customary casing:

• Classes - Initial Caps (Pascal Casing)
• Variables - Initial lowecase (Camel case)
• Methods - Initial lowecase (Camel case)

 Camel versus Pascal Casing

Perl is case sensitive.

print "hello"; //This works.

Print "hello"; //This does not.

Curly braces are used to bracket code blocks including classes and the methods within a class.

For Java, JavaScript, PHP, and C++, I prefer to put the first { at the end of the first line of the code block as in the example above because I see moreJava codeformatted that way.

public class Dog {

  public bark() {

    System.out.println("Ruff");

  }

}

In Perl, you create the entire HTML page within your .PL script file using print commands.

For Perl, PHP, JavaScript, Java,and C++, I prefer to put the first { at the end of the first line of the code block as in this example because I see morePeal codeformatted that way.

$x = "Yes";

If ($x == "Yes") {
  print "Hello world";

  print "I am a Perl coder.";

}

Commenting Code
Java uses "//" for a single line comment and /* */ for a multiple line comment.

//Single line comment in MS (not ANSI compliant so do NOT use).
/* ANSI compliant single line comment. */
/*
Multiple line
comment.

*/

/*

* This is another popular way 

* to write multi-line comments.

*/

Commenting Code
Perl uses # for single line comments and Perl does NOT have a multiple line comment.

Compiler Directives (A special comment.)

Perl also uses compiler directives embedded in comments with #! as in:

#!/usr/local/bin/perl -w

#This is a comment in Perl.

In Perl, you declare constants using the use constant keywords:

use constant CONST_NAME => "Value";

Constants in Perl are case sensitive. A common standard in Perl is to use all-uppercase letters, with underscores to separate words within the name.

use constant FULL_NAME => 'Mike Prestwood';
use constant AGE => 38;

print "Your name is " . FULL_NAME . ".<br>";
print "You are " . AGE . ".<br>";

String literals are quoted as in "Prestwood". If you need to embed a quote use a slash in front of the quote as in \".

To specify a floating point literal between 1 and -1, you can preceed the decimal with a 0 or not (both work). In other words, preceding and following decimals are allowed (both 1. and 1.0 work as well as .1 and 0.1). In general, Java follows the IEEE 754 Binary Floating-Point Arithmetic standard.

System.out.println("Hello");

System.out.println("Hello \"Mike\".");

//Does Java evaluate this simple

//floating point math correctly? No!

if ((.1 + .1 + .1) == 0.3) {
  System.out.println("Correct");
} else {
  System.out.println("Not correct");
}

 Ref: http://www.ibm.com/developerworks/java/library/j-jtp0114/

String literals are quoted as in "Prestwood". If you need to embed a quote use a slash in front of the quote as in \".

To specify a floating point literal between 1 and -1, you can preceed the decimal with a 0 or not (both work). In other words, preceding and following decimals are allowed (both .1 and 0.1). Trailing decimals are also allowed (1, 1., and 1.0 are all equivalent and allowed).

print "Hello";

print "Hello \"Mike\".";

#Does Perl evaluate this simple

#floating point math correctly? No! 

if ((.1 + .1 + .1) == .3) {
  print("Correct");
} else {
  print("Not correct");
}

 Perl Literals (quote)

Variable names are case sensitive.

The Java basic types are boolean, byte, short, int, long, float, double, and char. You can also declare a variable to hold a particular instance of a class such as String.

int a;

int a, b;

int age = 43;

String FullName;

Perl is a loosely typed language with only three types of variables: scalars, arrays, and hashes. Use $ for a scalar variable, @ for an array, or % for a hash (an associative array).

The scalar variable type is used for any type of simple data such as strings, integers, and numbers. In Perl, you identify and use a variable with a $ even within strings.

#!/usr/local/bin/perl -w

 
print("Content-type: text/html\n\n");

$fullname = 'Mike Prestwood';
$Age = 38;
$Weight = 162.4;

 

print "Your name is $fullname.
";
print "You are $Age and weigh $Weight.
";

 Perl Variables ($x = 0;)