Here are two types of comments in PHP:

This will have no output because they are all comments.

Class declaration with one method that has a parameter.

// Class declaration with a method that has a parameter.

public class GradeBook
{
// display a welcome message to the GradeBook user
public void displayMessage( String courseName )
{
System.out.printf( “Welcome to the grade book for\n%s!\n”,
courseName );
} // end method displayMessage

} // end class GradeBook

Creating a GradeBook object and passing a String to its displayMessage method

// Create GradeBook object and pass a String to
// its displayMessage method.
import java.util.Scanner; // program uses Scanner

public class GradeBookTest
{
// main method begins program execution
public static void main( String args[] )
{
// create Scanner to obtain input from command window
Scanner input = new Scanner( System.in );

// create a GradeBook object and assign it to myGradeBook
GradeBook myGradeBook = new GradeBook();

// prompt for and input course name
System.out.println( “Please enter the course name:” );
String nameOfCourse = input.nextLine(); // read a line of text
System.out.println(); // outputs a blank line

// call myGradeBook’s displayMessage method
// and pass nameOfCourse as an argument
myGradeBook.displayMessage( nameOfCourse );
} // end main

} // end class GradeBookTest

OUTPUT:

Please enter the course name:CS101 Introduction to Java Programming

Welcome to the grade book forCS101 Introduction to Java Programming!

Class declaration with one method

// Class declaration with one method.
public class GradeBook
{
// display a welcome message to the GradeBook user
public void displayMessage()
{
System.out.println( “Welcome to Java Tutorials!” );
} // end method displayMessage

} // end class GradeBook

Creating an object of class GradeBook and calling its displayMessage method.

// Create a GradeBook object and call its displayMessage method.
public class GradeBookTest
{
// main method begins program execution
public static void main( String args[] )
{
// create a GradeBook object and assign it to myGradeBook
GradeBook myGradeBook = new GradeBook();

// call myGradeBook’s displayMessage method
myGradeBook.displayMessage();
} // end main

} // end class GradeBookTest

OUTPUT:
Welcome to Java Tutorials!

We display text in java using the System.out.print and System.out.println. System.out.print displays a text without adding a new line after the text while the System.out.println adds a new line after the text.

Here is an example:

//text printing program

public class displayText
{
//main method begins execution of Java application
public static void main (String[]args)
{
System.out.print(”Welcome to Java Tutorials.”);
} //end method main

} // end class displayText

Output of the program:
Welcome to Java Tutorials.

Use a pattern to identify the individual words in the string, and then count how many
times that pattern recurs:

<?php
// define string
$text = “Fans of the 1980 group will have little trouble recognizing ?
the group’s distinctive synthesized sounds and hypnotic dance beats,?
since these two elements are present in almost every song on the ?
album; however, the lack of diversity and range is troubling, and I’m ?
hoping we see some new influences in the next album. More
intelligent lyrics might also help.”;

// decompose the string into an array of “words”
$words = preg_split(’/[^0-9A-Za-z\']+/’, $text, -1, ?
PREG_SPLIT_NO_EMPTY);

// count number of words (elements) in array
// result: “59 words”
echo count($words) . ” words”;
?>

Use the str_split() function to break the string into fixed-length “chunks”:
<?php
// define string
$str = “The mice jumped over the cat, giggling madly ?
as the moon exploded into green and purple confetti”;

// define chunk size
$chunkSize = 11;

// split string into chunks
// result: [0] = The mice ju [1] = mped over t [2] = he cat, gig
// [3] = gling madly …
$chunkedArr = str_split($str, $chunkSize);
print_r($chunkedArr);
?>

Use the ord() function to get the ASCII code for a character:

<?php
// define character
$char = “\r”;

// retrieve ASCII code
// result: 13
$asc = ord($char);
echo $asc;
?>

Use the chr() function to get the character corresponding to an ASCII code:

<?php
// define ASCII code
$asc = 65;

// retrieve character
// result: “A”
$char = chr($asc);
echo $char;
?>

<?php
// define string
$str = “   this is a string with  lots of    emb e dd    ed whitespace    ”;

// remove all whitespace from the string
// result: “thisisastringwithlotsofembeddedwhitespace”
$newStr = ereg_replace(’[[:space:]]+’, ”, trim($str));
echo $newStr;
?>
To convert more then one whitespace to single whitespace

<?php
// define string
$str = “   this is a string with  lots of    emb e dd   ed  whitespace    ”;

// trim the whitespace at the ends of the string
// compress the whitespace in the middle of the string
// result: “this is a string with lots of emb e dd ed whitespace”
$newStr = ereg_replace(’[[:space:]]+’, ‘ ‘, trim($str));
echo $newStr;
?>