2 replies to this topic

[atrip25]

what could be the result based on different orders of evaluation? I'm not sure I totally understand order of evals? Is there different ways this code can be read or executed?

int fun(int *i) {

 	    (*i) += 5;

 	    return 4;    

	}

	

	int main() {

  	    int x = 3;	

  	    x = x + fun(&x);

	}

[Hignar]

Most programming languages will evaluate the right hand side of an assignment operation first. In your example

 x = x + fun(&x); 

the RHS will be evaluated first

 x + fun(&x)

Things are slightly complicated by the fact that you use fun() to alter the value of x, but again the RHS is evaluated first. fun() returns 4 but it has altered the value of x to 8 so the x on the LHS of the '+' is evaluated as 8. Thus the whole RHS of the assignment operation evaluates to 12, which is then assigned to x.

[JCoder]

This is undefined behaviour. You should never rely on order of evaluation of the operators other than && || !