您可以在Java中与增量运算符一起使用哪种操作数？

Question

I don't know what happens if I apply the increment operator on an expression in Java.

int ai[] = new ai[10];
ai[0]++;

// ***

class Car {
  public int yearMade = 0;
}

class Person {
  public Car myCar = new Car();
}

Person p = new Person();
p.myCar.yearMade++;

Can you increment an element of an array the way the first example is showing?

Can you increment a field in a class (I do know about encapsulation and getters/setters, my question is syntax-semantics oriented) the way I show in the second example?

I remember the age of C/C++. There used to be a problem with p -> x++, for example. You sometimes needed to enclose complex expressions in parentheses when using increment or decrement.

Thank you for any hints.

Answer 1

The answer to both your questions is "Yes, you can". Both p.myCar.yearMade and ai[0] are variables (an instance variable and a local variable, respectively) , and, thus, can be used as operands for any of these four operators.

4.12. Variables

A variable is a storage location and has an associated type, sometimes called its compile-time type, that is either a primitive type (§4.2) or a reference type (§4.3).

A variable's value is changed by an assignment (§15.26) or by a prefix or postfix ++ (increment) or -- (decrement) operator (§15.14.2, §15.14.3, §15.15.1, §15.15.2).

...

15.14.2. Postfix Increment Operator ++

At run time, if evaluation of the operand expression completes abruptly, then the postfix increment expression completes abruptly for the same reason and no incrementation occurs. Otherwise, the value 1 is added to the value of the variable and the sum is stored back into the variable. Before the addition, binary numeric promotion (§5.6.2) is performed on the value 1 and the value of the variable. If necessary, the sum is narrowed by a narrowing primitive conversion (§5.1.3) and/or subjected to boxing conversion (§5.1.7) to the type of the variable before it is stored. The value of the postfix increment expression is the value of the variable before the new value is stored.