Java logical test questions

Java logical test questions

I've been solving a few problems about logic tests for AP Computer Science but I happened to get stuck on a few questions.

Here are the directions from the website: Translate each of the following English statements into logical tests that could be used in an if/else statement. Write the appropriate logical test for each statement below. Assume that three int variables, x, y, and z, have already been declared.

These are the 2 questions I have problems with:

Either x or y is even, and the other is odd.

x and z are of opposite signs.

I've been trying to find these answers out for a couple of hours and I still have no clue. I would appreciate it if someone could guide me in the right direction. I understand this is "homework" but some definitive help would be very helpful.

Answer by Keith Randall for Java logical test questions

You'll need to use and (&&) and or (||) to make a logic formula. I'm not going to do yours, but here's another one:

x is bigger than both y and z or x is less than both y and z.

Translates to:

((x > y) && (x > z)) || ((x < y) && (x < z))  

You just need to figure out a formula for odd/even (hint - the low order bit) and for positive/negative (hint - compare with 0), and combine those with and/or.

Answer by Makoto for Java logical test questions

For the first question, if x (or y)^* is odd, y (or x) must be even, and vice versa. Checking for odd values implies that the modulo of x and 2 is 1 - from there, you would have to assert if y (or x) modulo 2 is 0 (to check for evenness).

For the second question, you would need to follow a chain of logic as such:

• X is positive (or greater than 0), which implies Z must be negative (or less than 0).
• Z is positive, which implies that X must be negative.

^{*: This is an exclusive or - I mean that you're either checking x or y, but not both at the same time.}

Answer by arshajii for Java logical test questions

First you have to fully understand the statement in order to put it into the language of a computer. For example,

x and y have the same sign

What this really means is:

( x is greater than or equal to 0 and y is greater than or equal to 0 ) or ( x is less than 0 and y is less than 0 )

Now it is easy to put this into Java:

(x >= 0 && y >= 0) || (x < 0 && y < 0)  

Of course, your questions can be solved via a similar method.

Answer by km1 for Java logical test questions

Putting it in plain english, for me anyhow.

If ((x is even AND y is odd) OR (x is odd AND y is even))  

For the other

If ((x gt or eq 0 AND y lt 0) OR (y gt or eq 0 AND x lt 0))  

Assuming 0 is positive.

Answer by Elgorath for Java logical test questions

Either x or y is even, and the other is odd.

The sum of an odd and even number is odd. The sum of two odd numbers is even and the sum of two even numbers are even.

So (x+y)%2!=0.

x and z are of opposite signs

This one is similar, you can do:

x*z<0  

Since 0 is neither negative or positive and

• neg * pos = neg
• neg * neg = pos
• pos * pos = pos

If you want to consider 0 and a negative number of opposite signs you can use (x >= 0) == (z < 0)

Answer by Rico for Java logical test questions

For the first question: x % 2 != y % 2 Second question: x * z < 0

Fatal error: Call to a member function getElementsByTagName() on a non-object in D:\XAMPP INSTALLASTION\xampp\htdocs\endunpratama9i\www-stackoverflow-info-proses.php on line 72