Hello, world!

High school/Jr. High

10 PRINT "HELLO WORLD"
20 END

First year in college

program Hello(input, output);
  begin
    writeln ('Hello world');
  end

Senior year in college

(defun hello
    (print
        (cons 'HELLO (list 'WORLD))))

New professional

#include <stdio.h>
main (argc,argv)
    int argc;
    char **argv;
{
    printf ("Hello World!\n");
}

Seasoned pro

#include <stream.h>
const int MAXLEN = 80;
class outstring;
class outstring {
   private:
   int size;
   char str[MAXLEN];
   public:
   outstring() { size=0; }
   ~outstring() {size=0;}
   void print();
   void assign(char *chrs);
};
void outstring::print() {
  int i;
  for (i=0 ; i< size ; i++)
    cout << str[i];
  cout << "\n";
  }
void outstring::assign(char *chrs) {
  int i;
  for (i=0; chrs[i] != '\0';i++)
     str[i] = chrs[i];
  size=i;
  }
main (int argc, char **argv) {
  outstring string;
    string.assign("Hello World!");
  string.print();
  }

Manager

George, I need a program to output a string "Hello World!"

But the correct tool for the job is

   #!/usr/bin/env python
   print 'Hello World!'
or:
   #!/usr/bin/env perl
   print 'Hello World!'

And, of course, the GUI version:

#!/usr/bin/wish
button .h -text "Hello" -command {puts "Hello World!"}
button .q -text "Quit" -command exit
pack .h .q