programming-for-dummies

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The Structure of a Ruby Program
The Structure of a Ruby Program
A Ruby program can consist of one or more commands:
print(‘What is your name? ‘ )
myname = gets()
puts( “Welcome to Ruby, #{myname}” )
Unlike other programming languages, Ruby programs don’t need to define a
main program, don’t enclose blocks of commands with curly brackets, and
don’t end statements with a semicolon. Type a command, and Ruby obeys
without its syntax interfering with your thinking.
The preceding Ruby program simply asks the user to type in a name.
Whatever name the user types gets stored in the myname variable. Then the
last line prints the string “Welcome to Ruby,” followed by the contents of
the myname variable.
Creating Comments
To write a comment in Ruby, use the # symbol. Anything that appears to the
right of the # symbol is considered a comment, which the computer ignores.
# This is a comment
print(‘What is your name? ‘ )
myname = gets() # This is also a comment
puts( “Welcome to Ruby, #{myname}” )
If you want to write a comment over multiple lines, define the start and end
of a comment block with =begin and =end, such as
=begin This is a block of comments
that make it easy to comment
out multiple lines. However,
Ruby’s block commenting is kind
of ugly so it’s rarely used.
=end
print(‘What is your name? ‘ )
myname = gets()
puts( “Welcome to Ruby, #{myname}” )
Defining comments with the =begin and =end lines is often cumbersome, so
it’s more common for programmers to use multiple # symbols in front of
each line instead like this:
# This program was written by John Doe
# on January 24, 2009. It took him a