ex21 - start with function.rb

# what is Function?
# function is a block of code can i use that multiple times throughout the program. by calling
# the name of function and not write the all of code one more time. it is more easy to read and
# understand, easy to maintain and easy to debug it. Functions can accept input parameters,
# allowing them to work with different data or perform variations of the same task.
# Parameters provide flexibility and allow functions to be more versatile. Functions can
# optionally return a value after performing their task. This enables functions to produce
# output that can be used by other parts of the program.
# ########
# Parameters?
# Is a list of inputs or data values that the program send to the function for make the processing on. (optional)
# Built-In Functions In Ruby

sum = (1..10).sum
puts sum

power = 5.pow(2)
puts power
floor = 12.40.floor
puts floor

length = "Ahmed".length
puts length

size = "Ahmed".size
puts size

include = "Mostafa Mohamed Ahmed".include?("Ahmed")
puts include

start_with = "Mostafa Mohamed Ahmed".start_with?("Mostafa")
puts start_with

end_with = "Mostafa Mohamed Ahmed".end_with?("Ahmed")
puts end_with