std::forward_list<T,Allocator>::resize (3) - Linux Manuals

std::forward_list<T,Allocator>::resize: std::forward_list<T,Allocator>::resize

NAME

std::forward_list<T,Allocator>::resize - std::forward_list<T,Allocator>::resize

Synopsis

void resize( size_type count ); (1)
void resize( size_type count, const value_type& value ); (2)

Resizes the container to contain count elements.
If the current size is greater than count, the container is reduced to its first count elements.
If the current size is less than count,
1) additional default-inserted elements are appended
2) additional copies of value are appended

Parameters

count - new size of the container
value - the value to initialize the new elements with

Type requirements

-
T must meet the requirements of DefaultInsertable in order to use overload (1).
-
T must meet the requirements of CopyInsertable in order to use overload (2).

Return value

(none)

Complexity

Linear in the difference between the current size and count. Additional complexity possible due to list traversal to reach the first element to erase/the end position to insert

Example

// Run this code

  #include <iostream>
  #include <forward_list>
  int main()
  {
      std::forward_list<int> c = {1, 2, 3};
      std::cout << "The forward_list holds: ";
      for(auto& el: c) std::cout << el << ' ';
      std::cout << '\n';
      c.resize(5);
      std::cout << "After resize up to 5: ";
      for(auto& el: c) std::cout << el << ' ';
      std::cout << '\n';
      c.resize(2);
      std::cout << "After resize down to 2: ";
      for(auto& el: c) std::cout << el << ' ';
      std::cout << '\n';
  }

Output:

  The forward_list holds: 1 2 3
  After resize up to 5: 1 2 3 0 0
  After resize down to 2: 1 2