Question

Assume that x and y are boolean variables and have been properly initialized.(x && y) || !(x && y) The result of evaluating the expression above is best described as (A) always true (B) always false (C) true only when x is true and y is true (D) true only when x and y have the same value (E) true only when x and y have different values

Answer 1

Answer:

(A) Always true

Explanation:

Given

Boolean variables x and y

Required

What is (x && y) || !(x && y)

Irrespective of what x or y is, the x && y is always true

Take for instance:

x = true;

y = true;

x&&y will also be true because the values of x and y were not altered

And this is true for whatever boolean value x or y assume

Having said that:

x&&y = true

So, the expression is analysed as follows:

(x && y) || !(x && y)

Substitute true for x&&y

(true) || !(true)

!(true) = false

So, the expression becomes:

true || false

|| represents the OR operator; and it returns true if at least one of the conditions is true.

By this:

true || false = true

Option (A) Always true answers the question.