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--- docs:programming:hello_world_examples [2006/09/23 01:48] – billh
+++ docs:programming:hello_world_examples [2008/08/03 00:25] (current) – external edit 127.0.0.1
@@ Line 2: / Line 2: @@
 ===== php =====
-^without variables^with variables^
+PHP can be embedded into an html file, and interpreted at runtime for dynamic web page content.  It can also be executed at the command line by using the php program.
-|<code>
+==== simple ====
+<code php>
 <?php
 	echo "Hello World!";
 ?>
-</code>|<code>
+</code>
+==== with functions and variables ====
+<code php>
 <?php
 	$myString = "Hello World!";
-	echo $myString;
+	function printMyString(){
+		global $myString;
+		echo $myString;
+	}
+	printMyString();
 ?>
-</code>|
+</code>
+===== ASP.NET =====
+<code asp>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+	"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html>
+	<head>
+		<title>Hello World - ASP.NET</title>
+<script runat="server" language="VB">
+	Sub Page_Load(sender As Object, e As EventArgs)
+		timeLabel.Text = DateTime.Now.ToString()
+	End Sub
+</script>
+	</head>
+	<body>
+		<p>Hello World!</p>
+		<p>The time is now:
+			<asp:Label runat="server" id="timeLabel" /></p>
+	</body>
+</html>
+</code>
 ===== html =====
-<code>
+HTML by itself does not have functions or variables.  It is a tagged language most commonly used to display a web page.
+==== simple ====
+<code html4strict>
 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
 <html>
@@ Line 30: / Line 63: @@
 ===== c =====
-^without variables^with variables^
+C is a procedural, structured language that does not have objects.  C is extended by other languages, such as C++ and Objective-C.
-|<code>
+==== simple ====
+<code c>
 #include <stdio.h>
@@ Line 38: / Line 72: @@
         return 0;
 }
-</code>|<code>
+</code>
+==== with functions and variables ====
+<code c>
 #include <stdio.h>
 const char * myString;
-int main(){
+void printMyString(){
+	printf("%s\n",myString);
+	return;
+}
+int main(int argc, char **argv){
         myString = "Hello World!";
-        printf("%s\n",myString);
+        printMyString();
         return 0;
 }
-</code>|
+</code>
 ===== objective-c =====
+Objective-C is an extension of c, so a simple version will not be shown here.
+==== with functions and variables ====
+<code objc>
+#import <Foundation/NSObject.h>
+#import <Foundation/NSString.h>
+@interface Hello:NSObject{
+    NSString *myString;
+}
+-(void)printMyString;
+@end
+@implementation Hello
+-(void)printMyString{
+    myString = [NSString stringWithString:@"Hello World!"];
+    NSLog(myString);
+}
+@end
+int main( int argc, const char *argv[] ) {
+    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
+    Hello *h = [[Hello alloc] init];
+    [h printMyString];
+    [pool release];
+    return 0;
+}
+</code>
 ===== cpp =====
+* At least on the Mac platform, use g++ instead of gcc to compile because it already has the C++ standard libraries linked.
+==== simple ====
+<code cpp>
+#include <iostream>
+int main()
+{
+	std::cout << "Hello World!\n";
+	return 0;
+}
+</code>
+==== with classes, functions, and variables ====
+<code cpp>
+#include <iostream>
+#include <string>
+using namespace std;					// or type std:cout everywhere
+class Hello
+{
+	public:
+		Hello(const char * userString);		// Constructor
+		~Hello();				// Destructor
+		void printMsg();
+	private:
+		string privateString;			// private variable
+};
+Hello::Hello(const char * userString)
+{
+	privateString = userString;
+}
+Hello::~Hello()
+{
+	// do nothing special
+}
+void Hello::printMsg()
+{
+	cout << privateString;
+}
+int main()
+{
+	Hello HelloInstance("Hello World!\n");		// create a new instance
+	HelloInstance.printMsg();
+	return 0;
+}
+</code>
 ===== java =====
-^ plain ^ with functions and variables ^
+==== simple ====
-|<code>
+<code java>
 public class HelloWorld{
         public static void main(String args[]){
@@ Line 62: / Line 183: @@
         }
 }
-</code>|<code>
+</code>
+==== with methods and variables ====
+<code java>
 public class HelloWorldVar{
@@ Line 76: / Line 199: @@
         }
 }
-</code>|
+</code>
 ===== javascript =====
+===== perl =====
+==== simple ====
+<code perl>
+#!/usr/bin/perl
+print "Hello World!\n";
+</code>
+==== with functions and variables ====
+<code perl>
+#!/usr/bin/perl -w               # the 'w' tells perl to inform you of any
+                                 # warnings encountered
+#use strict;                     # tell perl to impose strict verification,
+                                 # and output additional warnings;
+                                 # it is commented out here because it will
+                                 # fail since the variable below requires
+                                 # an explicit package name (such as my)
+$myString = "Hello World!";      # $myString is a global variable
+sub printMyString {              # sub is used to define a subroutine, or
+                                 # function in perl;
+  print $myString . "\n";        # this instance of $myString references
+                                 # the global $myString variable;
+}
+sub printLocalString {
+  my $myString = "Hello Moon!";  # the my operator marks this instance of
+                                 # $myString as private;
+  print $myString . "\n";        # this statement is using the private
+                                 # $myString above;
+}
+printMyString();                 # call a subroutine
+printLocalString();              # call a subroutine
+</code>