Question

const ClassA& curShot = vec_shots[curShotIndx];

In the above code the curShot object is constructed and assigned at the same step. My question is which constructor is used in the above statement. I thought it will be the default constructor followed by the assignment operator, but it seems to call the copy constructor instead. Why is that the case?

Answer 1

What happens is that

vec_shots[curShotIndx];

returns a reference which you assign to const ClassA& curShot. There is no object creation involved in this step. Therefore no constructor is invoked (neither default nor copy constructor).

The assignment operator is not invoked either since you are not assigning one object instance to another, but only a reference. You are not handling more than one (existing) object instance in this code. So, no construction or assignment is invoked.