Introduction to Perl

1
Introduction to Perl

• Unit 2 Print More

2
The Print Function

• The print function is the easiest way to display
  your text to the screen.
• The Syntax for the print function is displayed as
  such
• print Your text here
• Programming languages are just like speaking
  languages, they all need to show when they are
  done. Periods are used for verbal languages and
  semicolons () are used in perl.
• To move text to the next line for the next print
  statement, finish the line with \n for next
  line. Also if you hit return before closing your
  quotes, you will have those returns in your
  output.

3
Same Thing Again Does it make any more sense
now?

• Print is a command ? you need to tell it what you
  want to print
• Ex. print I am a Winner! \n
• Your print statement ? quotes define what the
  print statement is going to say. Without them
  Perl does not know what you want to print
• Ex. print I am a Winner! \n
• ? must be at the end of (almost) every line
• Ex. print I am a Winner! \n
• \n ?\n is used as a carriage return
• Ex. print I am a Winner! \n

4
More With Print

• You can print variables using commas.name
  Tonyprint A name might be , name, \n
• You can print variables inside of quotes.name2
  Markprint Another popular name is name2
  \n

5
Pre-Programming Steps

• Before programming in any language, it is
  important to take note of a couple things. (Sorta
  like packing before going on vacation).
• What Variable Types/ of Variables Needed
• Can you program this in your head?
• Do you know all the functions you will need?
• Formulas
• Anything Else

6
Debugging

• Errors can be run time or compile time.
• Compile time errors give you a hint.
• The program wont run and the error is referenced
  by line number.
• For run time errors, print is your friend.
• Large numbers of print statements can clue you in
  on what your program is doing.

7
Commenting Reminder

• Commenting is done in Perl to make your code
  more understandable to other coders as well as to
  help you pick up where you left off.
• Comments in Perl are marked with the hash sign
  () which works like to the double slashes ( // )
  in C or Java.
• e.g. Insert Comments Here
• Be sure to use comments where appropriate

Print Exercises