# Measuring function execution time in
# Ruby using a reusable Timer (milliseconds + seconds)
# ---------------------------
# Reusable Timer class
# ---------------------------
class Timer
def initialize
@start = 0.0
@end = 0.0
end
# Start the timer
def start
@start = Process.clock_gettime(Process::CLOCK_MONOTONIC) # high‑precision timer
end
# Stop the timer
def stop
@end = Process.clock_gettime(Process::CLOCK_MONOTONIC)
end
# Return elapsed time in milliseconds
def elapsed_milliseconds
(@end - @start) * 1000.0
end
# Return elapsed time in seconds
def elapsed_seconds
@end - @start
end
end
# ---------------------------
# Function to measure
# ---------------------------
def work
sum = 0
100_000_000.times { |i| sum += i }
end
# ---------------------------
# Main program
# ---------------------------
t = Timer.new
t.start
work
t.stop
ms = t.elapsed_milliseconds
sec = t.elapsed_seconds
puts "Execution time: #{ms} ms"
puts "Execution time: #{sec} seconds"
=begin
run:
Execution time: 5167.134837014601 ms
Execution time: 5.167134837014601 seconds
=end
