IO: sketch that tests different methods for reading files one line or more at a time.

gistfile1.rb

# filename: files_line.rb
# sketch that tests different methods for reading files one line or more at a time.

# open file to read
puts
puts "Creating a reference to file input stream"
f = File.new("../chapter_11/regex_scan.rb")

# find out what approach to use to read the file
puts "Select a line-based approach to read the file:"
puts "	1) read method"
puts "	2) each method"
puts "	3) gets method"
puts "	4) readline method"
puts "	5) readlines method"
input = STDIN.gets.to_i
puts

# if input was 1 then use read method
if input == 1
	puts "** READ method: "
	puts f.read

# if input was 2 then use each method
elsif input == 2
	puts "** EACH method: "
	f.each { |n| puts n }

# if input was 3 then use gets method
elsif input == 3
	puts "** GETS method: "
	line = ""
	# loop through file f until f.gets = nil
	puts line while (line = f.gets)

# if input was 4 then use readline method
elsif input == 4
	puts "** READLINE method: "
	line = ""
	# loop through file f until f.readline returns an error
	puts line while (line = f.readline)

# if input was 5 then use readlines each method
elsif input == 5
	puts "** READLINES method: "
	lines = f.readlines
	puts "#{lines}"

# if input did not match then display error message
else 
	puts "** ERROR: your input didn't make sense"
end

puts

# close the file
f.close