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

Question

This question already has an answer here:

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• Undefined behavior and sequence points 5 answers
• How are java increment statements evaluated in complex expressions 1 answer
• Pre- & Post Increment in C# 6 answers

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 1

Answer 2

| Trace

int a= 2;                     a=2
int b= a++ + a++;             a=2, a=3

here value of a=4

int c = ++a + a++ + a++;      a=5, a=5, a=6

here value of a=7

In C/C++

Statement Trace

int a= 2;                     a=2
int b= a++ + a++;             a=2, a=2

here value of a=4

int c = ++a + a++ + a++;      a=5, a=5, a=5

here value of a=7

In short in java expression goes left to right so at the 2nd "a" it will fetch new value and in c/c++ it will first evaluate whole expression and then increment all operands of statement.

Answer 3

I like this question and found very good explanations but I just want to explain this question by it's value how it is evaluated:

I will only talk about java and c/C++ as I have no knoledge about C#

Statements are evaluated in following ways

In java

Statement

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Answer 4

Answer 5

Answer 6