Question

A programmer compares x == y, where x and y are doubles. For values that a programmer expects to be equal, the comparison will:

a) always be true
b) always be false
c) depend on specific values
d) result in a compilation error

Answer 1

Comparing two double values with 'x == y' depends on specific values due to floating-point representation in programming languages. A tolerance check is preferred for determining equality.

Step-by-step explanation:

When a programmer compares two double values using x == y, the comparison can sometimes result in unexpected behavior. Due to the way floating-point numbers are represented in most programming languages, two values that appear equal might not always be precisely the same when stored in memory. This is because of potential rounding errors or the result of previous calculations. Therefore, the comparison x == y for doubles will c) depend on specific values.

It is often better to check if the absolute difference between the two numbers is within a small tolerance range to determine if they are effectively equal. For example, one might use Math.abs(x - y) < epsilon, where epsilon is a small constant such as 1e-10, to account for possible precision differences.