Real newbie question about methods

Ruby
1

Hi all. I’m trying to learn ruby using about 5 books(!) but keep
struggling over basic things that are obvious to you guys but don’t
seem to be explained in a way my brain understands. Ruby is my first
programming language, by the way. Here is first one.

I have written this script (which works fine):-

target = 18…30
print 'please enter your age: ’
age = gets.chomp.to_i
if age < 18
puts ‘sorry, too young.’
elsif target === age
puts ‘have a great holiday.’
elsif age > 31
puts ‘sorry, too old.’
end
gets

What I want to do is put this in a method:-

def check_age(age)
print "Please enter your age: "
age = gets.chomp.to_i
eligible = 18…30

if age < 18
print “Sorry, too young.”
elsif eligible === age
print “Have a great holiday!”
else
print “Input not understood.”
check_age(age) # trying recursion here
end
check_age()
end

But it doesn’t work. How do I get the value entered by the user into
the method parameter?

Many thanks

2

On 7/10/06, simonh [email protected] wrote:

else
Many thanks

Probably something like:

def check_age(age)
eligible = 18…30
if age < 18
print “Sorry, too young.”
elsif eligible === age
print “Have a great holiday!”
true # provide a positive result
else
print “Input not understood.”
end
end

print "Please enter your age: "
check_age(gets.chomp.to_i)

of course I would use a case

make eligble a constant

and if required provide the flow control (probably not recursive) in

another function

Good luck
pth

3

simonh [email protected] wrote:

But it doesn’t work. How do I get the value entered by the user into
the method parameter?

def check_age
print "Please enter your age: "
age = gets.chomp.to_i
eligible = 18…30

if age < 18
print “Sorry, too young.”
elsif eligible === age
print “Have a great holiday!”
else
print “Input not understood.”
check_age # trying recursion here
end
end

check_age

works fine

4

On Jul 10, 2006, at 10:40 AM, simonh wrote:

print "Input not understood."

check_age(age) # trying recursion here
end
check_age()
end

you don’t want recursion.

def check_age(age)
eligible = 18…30
if age < 18
print “Sorry, too young.”
elsif eligible === age
print “Have a great holiday!”
else
print “Input not understood.”
end
end

print "Please enter your age: "
age = gets.chomp.to_i
check_age(age)

– Elliot T.

5

Thanks Une bévue

It seems I didn’t need the parameter to the method. Also forgot to add
the second elsif (to check if too old). If I run the program and type
‘a’ instead of a two digit number the first if statement gets printed -
‘sorry too young’

what i want is for the else statement to be run if user input is not
entered as two digits. How would I do this? Somehow got to check if
gets recieves an integer of two digits.

thanks again

6

On Jul 10, 2006, at 11:15 AM, simonh wrote:

gets recieves an integer of two digits.
use regex. if they enter a number it will match /\d+/

– Elliot T.

7

On Jul 10, 2006, at 11:33 AM, Elliot T. wrote:

‘sorry too young’

what i want is for the else statement to be run if user input is not
entered as two digits. How would I do this? Somehow got to check if
gets recieves an integer of two digits.

use regex. if they enter a number it will match /\d+/

umm better use anchors to be sure they only enter a number

/^\d+$/ if i recall correctly

– Elliot T.

8

You can add a regular expression to see if you age is valid like this:

/-----------------------------------------------------------------/
valid = /\d{2}/ #checks for exactly 2 digits
if valid.match(age)

else
puts “Invalid entry”
end

/-----------------------------------------------------------------/
Hope this helps.

_Steve

9

One correction: make age a string (.to_s) if you want to use the regexp

_<

I think Une’s code is cleaner overall.

_Steve

10

[email protected] [email protected] wrote:

valid = /\d{2}/ #checks for exactly 2 digits

this woundn’t help because of gets.chomp returns always strings and
gets.chomp.to_i returns Fixnum with 0 in case of any alpha betic char in
gets…

11

On Jul 10, 2006, at 12:00 PM, Une bévue wrote:

[email protected] [email protected] wrote:

valid = /\d{2}/ #checks for exactly 2 digits

this woundn’t help because of gets.chomp returns always strings and
gets.chomp.to_i returns Fixnum with 0 in case of any alpha betic
char in
gets…

so check the regex before the to_i

need anchors though or “hi24” will pass

– Elliot T.

12

Agreed that the regexp wouldn’t work for your code. I would have
written it like this (like I said before your code is cleaner)

def check_age
print "Please enter your age: "
age = gets.chomp
target = 18…30
valid = /\d{2}/

if valid.match(age)
if target === age.to_i
puts ‘Have A Nice Holiday’
elsif age.to_i < 18
puts ‘Too Young’
elsif age.to_i > 30
puts ‘Too Old’
end
else
puts “Usage: <18…30>”
check_age # Try again
end
end

check_age

_Steve

13

simonh [email protected] wrote:

It seems I didn’t need the parameter to the method. Also forgot to add
the second elsif (to check if too old). If I run the program and type
‘a’ instead of a two digit number the first if statement gets printed -
‘sorry too young’

what i want is for the else statement to be run if user input is not
entered as two digits. How would I do this? Somehow got to check if
gets recieves an integer of two digits.

def check_age
print "Please enter your age: "
age = gets.chomp.to_i
eligible = 18…30

if age == 0
print “Please enter a two digits number in « 18…30 ».”
check_age
elsif eligible === age
print “Have a great holiday!”
else age < 18
print “Sorry, too young.”
end
end

check_age

the “gets.chomp.to_i” returns 0 when only alphabetic chars. ie :

“toto” => 0

or :

“blahblah27yyyiyiyiyui” => 0

14

Go for it. We’re here to help >_<

15

[email protected] wrote:

if target === age.to_i

end

check_age

_Steve

thanks Steve, I like that. a nested if that checks against a rexexp
first. mind if I add it to my Library Of Useful Code Samples For When I
Get Stuck?

16

thanks for all the help everyone. things that were dark are now much
lighter.