What does this mean *((int*)(&val) +1)

[c320]

Hello,

I'm trying to understand this line of code. Can someone help me? Is it saving the result in the variable val or in the address of the variable val?

  *((int*)(&val) +1)= A*(y) + (B - C)

[mbozzi]

Neither. It treats val as an integer pointer, offsets it by one, obtains a reference to the pointed-to memory location, and copy-assigns the right-hand side to that referent.

Let's look at the lvalue expression -- the stuff on the left:
*((int*)(&val) +1)
We know from parentheses and the precedence rules which happens in what order. Starting from the inside,

(&val) Take the address of val.
(int*)(&val) Treat it as an integer pointer.
((int*)(&val) +1) Advance to address the next integer.
*((int*)(&val) +1) Obtain a reference to the next integer to val.

The referent then gets assigned the value of the right-hand side.

[keskiverto]

You did not show the type of val. It does not affect the explanation, but one would like to know why the explicit cast to int* is used.