class UnitCircle
def prompt
puts "Enter a number: "
#number = gets
#number = #number.to_i
puts "Enter a trigonometric equation to perform on that number: "
#eqn = gets
end
end
uc = UnitCircle.new
uc.prompt
num = Math.send(uc.instance_eval {#eqn}, uc.instance_eval {#number})
When I try to run it with say,
#number = 30
#eqn = sin
I get a no method error, why?
class UnitCircle
def prompt
puts "Enter a number: "
#number = gets.chomp
#number = #number.to_i
puts "Enter a trigonometric equation to perform on that number: "
#eqn = gets.chomp
end
end
gets method will include the new line symbol "\n". So you have to chomp it.
If you do not chomp, you will end up calling method "sin\n" instead of "sin"
Related
I created a calculator in ruby. I am wondering how to put this in a loop so I don't have to run it constantly. I am new to programming so please understand I am I just trying to learn. I would appreciate any help provided.
puts "Hello, My name is Calvin The Calculator and I am a calculator that can do basic functions such as Adding, Subtracting, Multiplying and Dividing"
puts "Press a and enter to enable my services"
enable = gets.chomp
if enable == "a"
puts "Choose which operation you want to do. + for adding, - for subtraction, * for multiplication and / for division"
else
"Puts Im Waiting..."
end
which_operation = gets.chomp
if which_operation == "+"
puts "What is the first number you want to add"
adding_first_number = gets.chomp.to_i
puts "What is the second number you want to add to #{adding_first_number}"
adding_second_number = gets.chomp.to_i
puts "#{adding_first_number} + #{adding_second_number} is #{adding_first_number + adding_second_number}"
else
end
if which_operation == "-"
puts "What is the first number you want to subtract"
subtracting_first_number = gets.chomp.to_i
puts "What is the number you want to subtract from #{subtracting_first_number}"
subtracting_second_number = gets.chomp.to_i
puts "#{subtracting_first_number} - #{subtracting_second_number} is #{subtracting_first_number - subtracting_second_number}"
else
end
if which_operation == "*"
puts "What is the first number you want to multiple"
multiplying_first_number = gets.chomp.to_i
puts "What is the number you want to multiple #{multiplying_first_number} by"
multiplying_second_number = gets.chomp.to_i
puts "#{multiplying_first_number} * by #{multiplying_second_number} is #{multiplying_first_number * multiplying_second_number}"
else
end
if which_operation == "/"
puts "What is the first number to your divison question?"
dividing_first_number = gets.chomp.to_i
puts "What is the divisor?"
dividing_second_number = gets.chomp.to_i
puts "#{dividing_first_number} divided by #{dividing_second_number} is #{dividing_first_number / dividing_second_number}"
else
end
For example:
until (which_operation = gets.chomp).empty?
if which_operation == "+"
...
end
if which_operation == "-"
...
end
if which_operation == "*"
...
end
if which_operation == "/"
...
end
end
This loop will work until you press Enter without entering any text before it.
P.S.: Better use case operator instead of multiple if.
P.P.S.: All your code, after loop addition and without case operator, will be:
puts "Hello, My name is Calvin The Calculator and I am a calculator that can do basic functions such as Adding, Subtracting, Multiplying and Dividing"
puts "Press a and enter to enable my services"
until gets.chomp == "a"
puts "I'm Waiting..."
end
puts "Choose which operation you want to do. + for adding, - for subtraction, * for multiplication and / for division"
until (which_operation = gets.chomp).empty?
if which_operation == "+"
puts "What is the first number you want to add"
adding_first_number = gets.chomp.to_i
puts "What is the second number you want to add to #{adding_first_number}"
adding_second_number = gets.chomp.to_i
puts "#{adding_first_number} + #{adding_second_number} is #{adding_first_number + adding_second_number}"
elsif which_operation == "-"
puts "What is the first number you want to subtract"
subtracting_first_number = gets.chomp.to_i
puts "What is the number you want to subtract from #{subtracting_first_number}"
subtracting_second_number = gets.chomp.to_i
puts "#{subtracting_first_number} - #{subtracting_second_number} is #{subtracting_first_number - subtracting_second_number}"
elsif which_operation == "*"
puts "What is the first number you want to multiple"
multiplying_first_number = gets.chomp.to_i
puts "What is the number you want to multiple #{multiplying_first_number} by"
multiplying_second_number = gets.chomp.to_i
puts "#{multiplying_first_number} * by #{multiplying_second_number} is #{multiplying_first_number * multiplying_second_number}"
elsif which_operation == "/"
puts "What is the first number to your divison question?"
dividing_first_number = gets.chomp.to_i
puts "What is the divisor?"
dividing_second_number = gets.chomp.to_i
puts "#{dividing_first_number} divided by #{dividing_second_number} is #{dividing_first_number / dividing_second_number}"
end
puts "\nLet's try again: "
end
I have to create a program where I have to ask the user for their first and last name on a single line. If the user puts only their first OR last name, it will be rejected through the exception. I keep getting an error at the end (below).
class MyNewException < Exception
attr_accessor :first, :last
def initialize (first, last)
#first = first
#last = last
end
end
print "Enter your first and last name:"
begin
first, last = gets.chomp.split
print "Hello," + first + " " + last + "!"
if last.size == 0
raise MyNewException, "Sorry, I didn't catch that! Try again:"
end
rescue MyNewException
puts "Sorry, I didn't catch that. Try again:"
retry
end
Keep getting an error:
testing.rb:15:in `+': no implicit conversion of nil into String (TypeError)
The raise() docs are faulty. You can do this:
puts "Enter your first and last name:"
name = gets.chomp
class MyNewException < Exception
def initialize(str)
super(str) #pass the value for the message property to the parent class
end
end
begin
raise MyNewException, "Sorry, I didn't quite catch that! Try again:"
rescue MyNewException => e
puts e.message
end
--output:--
Enter your first and last name:
Sarah Kim
Sorry, I didn't quite catch that! Try again:
Or:
puts "Enter your first and last name:"
name = gets.chomp
class MyNewException < Exception
attr_accessor :first, :last
def initialize(user_name, exception_message)
#first, #last = user_name.split
super exception_message
end
end
begin
raise MyNewException.new(name, "I didn't quite catch that! Try again:")
rescue MyNewException => e
puts e.message
puts e.first
puts e.last
end
--output:--
Enter your first and last name:
Sarah Kim
I didn't quite catch that! Try again:
Sarah
Kim
Here's how to write an infinite loop to get user input:
class Person
attr_accessor :first, :last
def initialize(first, last)
#first = first.capitalize
#last = last.capitalize
end
end
while true
puts "Enter your first and last name:"
first, last = gets.chomp.split
#Show what you got:
p first
p last
if first and last
#If no names were entered, both first and last will be nil.
#If one name was entered, first will evaluate to true and last will be nil.
#If two names were entered, first and last will evaluate to true.
#If two or more names were entered, first and last will evaluate to true.
user = Person.new first, last
break #jump to the line immediately after the infinite loop
end
puts "Sorry, you must enter both a first and a last name. Try again"
end
puts "Thanks #{user.first} #{user.last}!"
Create a loop that do your trial and error.
as for my answer I choose while loop
i = 0
while i < 1 do
if condition == true
# display your greetings then increment loop to end
i += 1
else
# display error message
end
end
So your code would be like this
class MyNewException < Exception
attr_accessor :first, :last, :valid
def initialize(first, last)
#first = first
#last = last
#valid = true
if first.empty? || last.empty? then
#valid = false
end
end
end
i = 0
while i < 1 do
print "Enter your first name: "
firstname = gets.chomp
print "Enter your last name: "
lastname = gets.chomp
name = MyNewException.new(firstname, lastname)
if name.valid then
puts "Greetings " << name.first << " " << name.last
i += 1
else
puts "I didn't quite catch that! Try again:"
end
end
I have this code:
#!/usr/local/bin/env ruby
require 'digest'
require 'digest/bubblebabble'
require 'base64'
require 'colored'
def sha256(info)
Digest::SHA256.digest "#{info}"
end
def sha256_hex(info)
Digest::SHA256.hexdigest "#{info}"
end
def sha256_base64(info)
Digest::SHA256.base64digest "#{info}"
end
def md5(info)
encrypt = Digest::MD5.new
encrypt << "#{info}"
encrypt.hexdigest
end
def bubblebabble(info)
Digest::SHA256.bubblebabble "#{info}"
end
def base64(info)
Base64.encode64("#{info}")
end
def start_encryption
puts "Choices include:",
"1. SHA256",
"2. SHA256 HEX",
"3. SHA256 BASE64",
"4. MD5",
"5. SHA256 BUBBLEBABBLE",
"6. BASE64"
print "\nWhat would you like to encrypt to: "
input = gets.chomp.to_i
case
when 1
print "Enter string: "
input = gets.chomp
sha = sha256(input)
puts "\n#{sha}".green.bold
when 2
print "Enter string: "
input = gets.chomp
sha_hex = sha256_hex(input)
puts "\n#{sha_hex}"
when 3
print "Enter string: "
input = gets.chomp
sha_64 = sha256_base64(input)
puts "\n#{sha_64}".green.bold
when 4
print "Enter string: "
input = gets.chomp
md5_encrypt = md5(input)
puts "\n#{md5_encrypt}".green.bold
when 5
print "Enter string: "
input = gets.chomp
babble = bubblebabble(input)
puts "\n#{babble}".green.bold
when 6
print "Enter string: "
input = gets.chomp
base64_encrypt = base64(input)
puts "\n#{base64_encrypt}".green.bold
end
end
start_encryption
Basic encryption tool. However when trying to encrypt for some reason in the CMD on windows 8 it shows up like this:
Does anybody have any idea why it's doing this? Is there a certain encoding I need to play with?
I got it to work with a minor change to your code:
input = gets.chomp.to_i
case
when 1
Should instead be
input = gets.chomp.to_i
case input
when 1
Enter string: America
088f003833d523d9dccc529e929afdc7
I have a class called PolynomialElements and inside that class I have a method called printElement that has a puts statement that print two variables. The puts statement is printing the variables on different lines. How do I get puts to print the two variables on one line. My code is below, it is line #5 where the puts statement is.
class PolynomialElements
attr_accessor :element, :size
def printElement
puts "#{element}x^#{size}"
end
end
askAgain = true
polyArray = Array.new
while askAgain
puts "How many numbers do you want to enter? "
numString = gets
num = numString.to_i
while num > 0
puts "Enter a value for the Polynomial "
value = gets
polyArray.push(value)
num -= 1
end
sizeOfArray = polyArray.length
polyArray.each do |x|
var = PolynomialElements.new
var.element = x
sizeOfArray -= 1
var.size = sizeOfArray
var.printElement
end
puts "Enter y to enter new number or anything else to quit"
cont = gets
if cont.chomp != "y"
askAgain = false
else
polyArray.clear
end
end
In the while loop change:
value = gets
to:
value = gets.chomp
You will then get:
Enter a value for the Polynomial
3
1x^2
2x^1
3x^0
Hi Im getting an core error which is really standard I suppose in Ruby but dont know what to make of it. I have a program that I have written. Its purpose is to register guests at a camping. You have a menu with 5 different options. 1. Checkin. When i do this I get a undefined method generateParkingLot' for #<Camping:0x10030a768> (NoMethodError)
When I choose Checkout I get a undefined local variable or methoddeparture' for Menu:Class (NameError).
So please i someone has a clue to my problem it would be great. I will here paste all my code. The code is separated in different files and I have used require for the different files. Here though I will paste all the code in one trace. Thankful for all help.
-Sebastien
require 'guest'
require 'parking_lot'
class Camping
attr_accessor :current_guests, :parking_lots, :all_guests, :staticGuests
def initialize(current_guests, parking_lots, all_guests, staticGuests)
#current_guests = Array.new()
# initiera husvagnsplatserna
#parking_lots = Array.new(32)
32.times do |nr|
#parking_lots[nr] = Parking_Lot.new(nr)
#staticGuests = Array[
Guest.new("Logan Howlett", "Tokyo", "07484822",1, #parking_lots[0]),
Guest.new("Scott Summers", "Chicago", "8908332", 2, #parking_lots[1]),
Guest.new("Hank Moody", "Boston", "908490590", 3, #parking_lots[2]),
Guest.new("Jean Grey", "Detroit", "48058221", 4, #parking_lots[3]),
Guest.new("Charles Xavier","Washington DC", "019204822",5, #parking_lots[4])
]
end
#all_guests = []
#staticGuests.each do |guest|
#current_guests[guest.plot.nr] = guest
#all_guests.push(guest)
end
end
def to_s
# creates an empty string
list = " "
# loop from 1 to 32
(1..32).each do |n|
if (!#current_guests[n-1].nil?)
list += #current_guests[n-1].to_s
else
# else adds the text "Vacant"
list += n.to_s + ": Vacant!\n"
end
return list
end
def generateParkingLot
randomNr = 1+rand(32)
# exists a guest at the (0-based) position?
if (!#current_guests[randomNr-1].nil?)
# if so generate a new figure
generateEmpty(array)
else
# returns the generated number
return randomNr
end
end
end
end
class Guest
attr_accessor :firstname, :lastname, :address, :phone, :departure
attr_reader :arrived, :plot
def initialize (firstName, lastName, address, phone, plot)
#firstName = firstName
#lastName = lastName
#address = address
#phone = phone
#arrived = arrived
#plot = plot
end
def to_s
"Personal information:
(#{#firstName}, #{#lastName}, #{#address}, #{#phone}, #{#arrived}, #{#departure}, #{#plot})"
end
end
require 'ruby_camping'
require 'camping_guests'
class Main
if __FILE__ == $0
$camping = Camping.new(#current_guests, #all_guests, #parking_lots,#staticGuests)
puts "\n"
puts "Welcome to Ruby Camping!"
while (true)
Menu.menu
end
end
end
require 'date'
require 'camping_guests'
require 'guest'
class Menu
def initialize(guests = [])
#camping = Camping.new(guests)
end
def self.menu
puts "---------------------------"
puts " Menu"
puts " 1. Checkin"
puts " 2. Checkout"
puts " 3. List current guests"
puts " 4. List all guests"
puts " 5. Exit\n"
puts ""
puts " What do you want to do?"
puts "---------------------------"
print ": "
action = get_input
do_action(action)
end
# fetches menu choice and returns chosen alternativ
def self.get_input
input = gets.chomp.to_i
while (input > 5 || input < 1) do
puts "Ooups, please try again."
input = gets.chomp.to_i
end
return input
end
def self.do_action(action)
case action
when 1:
check_in
when 2:
check_out
when 3:
puts $camping.current_guests
when 4:
puts $camping.all_guests
when 5:
puts "You are now leaving the camping, welcome back!"
exit
end
end
def self.check_in
puts "Welcome to the checkin"
puts "Please state your first name: "
firstName = gets.chomp
puts "Please state your last name:"
lastName = gets.chomp
puts "Write your address: "
address = gets.chomp
puts "and your phone number: "
phone = gets.chomp
puts "finally, your arrival date!"
arrived = gets.chomp
newPLot = $camping.generateParkingLot
newGuest = Guest.new(firstName, lastName, address, phone,arrived,$camping.parking_lots[newPLot-1])
$camping.current_guests[newPLot-1] = newGuest
#all_guests.push(newGuest)
puts "The registration was a success!! You have received the " + newPLot.to_s + "."
end
def self.check_out
puts "Welcome to checkout!"
puts $camping.all_guests
puts "State plot of the person to checkout!"
plot = gets.chomp.to_i
puts "Ange utcheckningsdatum: "
departureDate = gets.chomp.to_i
guest = $camping.current_guests[plot-1]
#departure = departure
guest.departure = departureDate
guestStayedDays = departureDate - guest.arrived
guest.plot.increase(guestStayedDays)
puts guest
$camping.current_guests[plot-1] = nil
end
end
class Parking_Lot
attr_accessor :nr
attr_reader :electricity_meter
def initialize (nr)
#nr = nr
#electricity_meter = 4000-rand(2000)
end
def increase_meter(days)
generatedUse = (10+rand(70))*days
puts "Increases the meter with " + generatedUse.to_s + " kWh."
#electricity_meter += generatedUse
end
def to_s
"Plot #{#nr+1} Electricity meter: #{#electricity_meter} kWh"
end
end
It looks (although I haven't tried this out) like some of your your 'end's are wrong.
The one which is causing your first error (generateParkingLot undefined) is that generateParkingLot is actually defined inside to_s, so you need an extra 'end' at the end of your to_s method.
As for the second error (departure not recognised), the folowing line in self.check_out is at fault:
#departure = departure
because there is no 'departure' variable. (Perhaps you meant DepartureDate?). I suspect there may be a few other issues with this code, but I'm afraid I don't really have time to check now.
One I noticed was that when you have
32.times do |nr|
#parking_lots[nr] = Parking_Lot.new(nr)
I think you might want to end that, either with an 'end' or curly brackets, e.g.
32.times do |nr|
#parking_lots[nr] = Parking_Lot.new(nr)
end
Although that would make your other blocks not match.. In general, just try and make sure your blocks are all defined properly (e.g. everything has a matching end).