clearing a vector or defining a new vector, which one is faster

Question

Which method is faster and has less overhead?

Method 1:

void foo() {
  std::vector< int > aVector;
  for ( int i = 0; i < 1000000; ++i ) {
              


        

Answer 1

The clear() is most likely to be faster, as you will retain the memory that has been allocated for previous push_back()s into the vector, thus decreasing the need for allocation.

Also you do away with 1 constructor call and 1 destructor call per loop.

This is all ignoring what you're compiler optimizer might do with this code.