Pre & post increment operator behavior in C, C++, Java, & C#

DISCLAIMER: This is not a real-world example. It is just a theoretical question of how these languages work.

What exactly are the differences between C/C++, C#, and Java when it comes to post & pre increment operators?

This is what I get with VC++10, Java 1.6, and C# 4

int a = 2;
int b = a++ + a++;
int c = ++a + a++ + a++;

      +-----+------+------+----+
      |  C  | C++  | Java | C# |
+-----+-----+------+------+----+
| a   |  7  |  7   |   7  |  7 |
+-----+-----+------+------+----+

| b   |  4  |  4   |   5  | 5  |
+-----+-----+------+------+----+
| c   | 15  |  15  |  16  | 16 |
+-----+-----+------+------+----+

Answer

Java and C# evaluate expressions from left to right, and the side-effects are visible immediately.

In C++, the order of evaluation of subexpressions is unspecified, and modifying the same object twice without an intervening sequence point is undefined behavior.