Which side of the assignment operator is evaluated first?
assignment-operator, c++, evaluation, function, order-of-execution
Solution
Order of evaluation would be unspecified in that case. Dont write such code
Similar example here
Problem
``` int& foo() { printf("Foo\n"); static int a; return a; } int bar() { printf("Bar\n"); return 1; } void main() { foo() = bar(); } ``` I am not sure which one should be evaluated first. I have tried in VC that bar function is executed first. However, in compiler by g++ (FreeBSD), it gives out foo function evaluated first. Much interesting question is derived from the above problem, suppose I have a dynamic array (std::vector) ``` std::vector<int> vec; int foobar() { vec.resize( vec.size() + 1 ); return vec.size(); } void main() { vec.resize( 2 ); vec[0] = foobar(); } ``` Based on previous result, the vc evaluates the foobar() and then perform the vector operator[]. It is no problem in such case. However, for gcc, since the vec[0] is being evaluated and foobar() function may lead to change the internal pointer of array. The vec[0] can be invalidated after executation of foobar(). Is it meant that we need to separate the code such that ``` void main() { vec.resize( 2 ); int a = foobar(); vec[0] = a; } ```