23 Containers library [containers]

23.3 Sequence containers [sequences]

23.3.5 Class template list [list]

23.3.5.3 list capacity [list.capacity]

void resize(size_type sz);

1

Effects: If size() < sz, appends sz - size() value-initialized elements to the sequence. If sz <= size(), equivalent to

list<T>::iterator it = begin();
advance(it, sz);
erase(it, end());
2

Requires: T shall be DefaultConstructible.

void resize(size_type sz, const T& c);

3

Effects: 

if (sz > size())
  insert(end(), sz-size(), c);
else if (sz < size()) {
  iterator i = begin();
  advance(i, sz);
  erase(i, end());
}
else
  ;                 // do nothing
4

Requires: T shall be CopyInsertable into *this.