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c#c++evaluationoperator-precedenceassociativity

How to make the C++ compiler to follow the same precedence, associativity and order of evaluation that C# has in the this assignment statement?

Consider the following piece of code:

int x = 1;
int y = 2;
y = x + (x = y);

When this runs in C#, the variables end up assigned with these values:

x = 2

y = 3

On the other hand, when the same runs in C++, the variables end like this:

x = 2

y = 4

Clearly, the C++ compiler is using different precedence, associativity and order of evaluation rules than C# (as explained in this Eric Lippert's article).

So, the question is:

Is it possible to rewrite the assignment statement to force C++ to evaluate the same as C# does?

The only restriction is to keep it as a one-liner. I know this can be rewritten by splitting the assignments into two separate lines, but the goal is to maintain it in a single line.

Solution

  • Yes, it is possible indeed.

    x = (y+=x) - x;

    So simple.