This is the first in a series for beginners on the Ruby Programming Language. Note that Ruby is a programming language. Ruby on Rails (“RoR”) is a web-application framework that is implemented in Ruby. Do not confuse the two. We will not covering Ruby on Rails in these tutorials.
# Variables and expressions.
a = 10
b = 3 * a + 2
printf("%d %d\n", a, b);
# Type is dynamic.
b = "A string"
c = 'Another String'
print b + " and " + c + "\n"
The variables shown in this example are “local variables”. (We’ll explore other possibilities later.)
Names are mostly conventional: letters, underscore, and digit, not starting with a digit. Local variables must start with a lower-case letter.
Variable types are dynamic: Assignment transfers both and type, not just value. Variables are not declared with a type, and assignment does not need to perform conversion.
+ concatenates strings, as in Java and C++.
printf function is lifted from plain C.