22 Containers library [containers]

22.3 Sequence containers [sequences]

22.3.10 Class template list [list] Capacity [list.capacity]

void resize(size_type sz);
Preconditions: T is Cpp17DefaultInsertable into *this.
Effects: If size() < sz, appends sz - size() default-inserted elements to the sequence.
If sz <= size(), equivalent to:
list<T>::iterator it = begin();
advance(it, sz);
erase(it, end());
void resize(size_type sz, const T& c);
Preconditions: T is Cpp17CopyInsertable into *this.
Effects: As if by:
if (sz > size())
  insert(end(), sz-size(), c);
else if (sz < size()) {
  iterator i = begin();
  advance(i, sz);
  erase(i, end());
  ;                 // do nothing