Never, ever, do that. The results are always undocumented and can vary from language to language and from compiler version to version.
Perhaps you should read the manual:
Important Notice int i=5; int k = i++ + ++i; Computational problems may occur while moving the above expression from one programming environment to another one (for example, from Borland C++ to MQL4). In general, the order of computations depends on the compiler implementation. In practice, there are two ways to implement the post-decrement (post-increment):… Arithmetic Operations - Operations and Expressions - Language Basics - MQL4 Reference
How To Ask Questions The Smart Way. 2004 How To Interpret Answers. RTFM and STFW: How To Tell You've Seriously Screwed Up.