if usr > User
if usr_pass > Pass
puts "Correct user and pass"
else
puts "Correct user"
puts "Wrong pass"
end
else
if usr_pass > Pass
puts "Correct pass"
else
puts "Wrong pass"
end
puts "Wrong user"
end
------------------------This is the same but in VB---------
if usr = User and usr_pass = Pass then
print "correct user and password"
else
if usr = User and usr_pass <> Pass then
print "correct user and wrong password"
else
if usr <> User and usr_pass = Pass then
print "correct password and wrong user"
else
if usr <> User and usr_pass <> Pass then
print "wrong password and wrong user"
end if
end if
end if
end if
-----------------------------------------------------
-------And how do i do this in ruby? ------
If usr = User and usr_pass = Pass then
print "Correct User and Pass"
else
print "Wrong User or Pass"
endif
if usr > User
if usr_pass > Pass
puts "Correct user and pass"
else
puts "Correct user"
puts "Wrong pass"
end
else
if usr_pass > Pass
puts "Correct pass"
else
puts "Wrong pass"
end
puts "Wrong user"
end
------------------------This is the same but in VB---------
if usr = User and usr_pass = Pass then
print "correct user and password"
else
if usr = User and usr_pass <> Pass then
print "correct user and wrong password"
else
if usr <> User and usr_pass = Pass then
print "correct password and wrong user"
else
if usr <> User and usr_pass <> Pass then
print "wrong password and wrong user"
end if
-----------------------------------------------------
-------And how do i do this in ruby? ------
If usr = User and usr_pass = Pass then
print "Correct User and Pass"
else
print "Wrong User or Pass"
endif
Question 1:
print "enter username: "
username = gets.chomp # chomp removes the last newline
print "enter password: "
password = gets.chomp
# using constants may not be the best approach...
Username = "foo"
Password = "bar"
if usr > User
if usr_pass > Pass
puts "Correct user and pass"
else
puts "Correct user"
puts "Wrong pass"
end
else
if usr_pass > Pass
puts "Correct pass"
else
puts "Wrong pass"
end
puts "Wrong user"
end
Btw, why do you compare with greater than and a string?
I didn't know how to compare so I just guessed it would be greater
than.
How would you do if you where to do a program like mine? The way you
wrote or any other way?
Well, you're testing for equality, so greater than wouldn't catch a lot of cases. I'd suggest these:
if X != Y # X not equal to Y
unless X == Y # X equal to Y
You can pick the one that's more linguistically appealing to you, though I have a hunch that 'if' is more popular than 'unless'.
matthew smillie.
···
On Aug 15, 2006, at 14:40, fabsy wrote:
Thanks!
Btw, why do you compare with greater than and a string?
I didn't know how to compare so I just guessed it would be greater
than.
How would you do if you where to do a program like mine? The way you
wrote or any other way?
That was my first intuition too, and I'm certain that's part of it, but upon further reflection I think there's more to it as well. To make an if and unless statement equivalent, you have to negate the condition, leading to this basic schema:
(1) if X != Y <--> unless X == Y
(2) if X == Y <--> unless X != Y
Logically, everything's kosher, but linguistically there's a crucial difference: the 'unless' form of (2) is a double negative. I'm sure people are generally familiar with the admonition to avoid double negatives in their writing, and it's for a good reason: people have a hard time understanding multiple negations; to be fair, two is usually not a problem, especially in familiar forms such as "not unlike X", but in general it's not an easy task to not do incorrectly. (see?)
So, if you assume that given the choice people won't use linguistically-uncomfortable code, then there are two basic comfortable 'if' forms, but only one comfortable 'unless' form. Given the lovely, literary nature of Ruby code, this seems like a reasonable assumption to make; so even if everyone were perfectly familiar with 'unless' as a language construct, you'd still expect 'if' to outnumber 'unless'.
Not that I think this has much bearing on the language, just a neat observation.
On Aug 15, 2006, at 15:05, Daniel Schierbeck wrote:
Matthew Smillie wrote:
if X != Y # X not equal to Y
unless X == Y # X equal to Y
You can pick the one that's more linguistically appealing to you, though I have a hunch that 'if' is more popular than 'unless'.
I only think that's because most other languages don't have `unless'
On Aug 15, 2006, at 15:05, Daniel Schierbeck wrote:
Matthew Smillie wrote:
if X != Y # X not equal to Y
unless X == Y # X equal to Y
You can pick the one that's more linguistically appealing to you, though I have a hunch that 'if' is more popular than 'unless'.
I only think that's because most other languages don't have `unless'
That was my first intuition too, and I'm certain that's part of it, but upon further reflection I think there's more to it as well. To make an if and unless statement equivalent, you have to negate the condition, leading to this basic schema:
(1) if X != Y <--> unless X == Y
(2) if X == Y <--> unless X != Y
Logically, everything's kosher, but linguistically there's a crucial difference: the 'unless' form of (2) is a double negative. I'm sure people are generally familiar with the admonition to avoid double negatives in their writing, and it's for a good reason: people have a hard time understanding multiple negations; to be fair, two is usually not a problem, especially in familiar forms such as "not unlike X", but in general it's not an easy task to not do incorrectly. (see?)
So, if you assume that given the choice people won't use linguistically-uncomfortable code, then there are two basic comfortable 'if' forms, but only one comfortable 'unless' form. Given the lovely, literary nature of Ruby code, this seems like a reasonable assumption to make; so even if everyone were perfectly familiar with 'unless' as a language construct, you'd still expect 'if' to outnumber 'unless'.
Not that I think this has much bearing on the language, just a neat observation.
Interesting thoughts (and cool example). I do however tend to use short, one-liner conditional statements the most, in which I think `unless' fits much nicer than `if not'.
