Читать книгу OCP Oracle Certified Professional Java SE 17 Developer Study Guide - Jeanne Boyarsky - Страница 152

One final thing to know about assignment operators is that the result of an assignment is an expression in and of itself equal to the value of the assignment. For example, the following snippet of code is perfectly valid, if a little odd-looking:

long wolf = 5; long coyote = (wolf=3); System.out.println(wolf); // 3 System.out.println(coyote); // 3

The key here is that (wolf=3) does two things. First, it sets the value of the variable wolf to be 3. Second, it returns a value of the assignment, which is also 3.

The exam creators are fond of inserting the assignment operator (=) in the middle of an expression and using the value of the assignment as part of a more complex expression. For example, don't be surprised if you see an if statement on the exam similar to the following:

boolean healthy = false; if(healthy = true) System.out.print("Good!");

While this may look like a test if healthy is true, it's actually assigning healthy a value of true. The result of the assignment is the value of the assignment, which is true, resulting in this snippet printing Good!. We'll cover this in more detail in the upcoming “Equality Operators” section.