Question

I want to know what are difference(s) between vector‘s push_back and insert functions.

Is there a structural difference(s)?

Is there a really big performance difference(s)?

Answer 1

The biggest difference is their functionality. push_back always puts a new element at the end of the vector and insert allows you to select new element’s position. This impacts the performance. vector elements are moved in the memory only when it’s necessary to increase it’s length because too little memory was allocated for it. On the other hand insert forces to move all elements after the selected position of a new element. You simply have to make a place for it. This is why insert might often be less efficient than push_back.