December 22, 2024
Answer to Booleans Q2
(a)
true
Explanation
aToad position - 10 == aFrog position | (aToad colour = aFrog colour )
this leads to
aToad position - 10 == aFrog position | (Brown = Green)
which evaluates to
aToad position - 10 == aFrog position | false
which evaluates to
11 - 10 == 1 | false
which evaluates to
1 == 1 | false
which evaluates to
true | false
which answers true
(b)
false
Explanation
aToad position - 10 == aFrog position | aToad colour = aFrog colour
Evaluating left to right and evaluating unary messages first leads to
11 - 10 == 1 | Brown = Green
This gives us four binary messages that will be evaluated from left to right
giving
1 == 1 | Brown = Green giving
true | Brown = Green
true | Brown returns true. Even if the argument
is not a Boolean, in this case the argument is Brown, sending the message
| Brown to true will answer true. This evaluates to
true = Green which returns false
This all goes to show how important those parentheses are.
(c)
false
Explanation
(aToad position - 10 == aFrog position) not & (aToad colour = aFrog colour) not
evaluates to
(11 - 10 == 1)not & ( Brown = Green) not
evaluates to
(1 == 1)not & ( false)not
evaluates to
true not & false not
evaluates to
false & true
which answers
false
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