C++ List resize

C++ List resize function changes the size of the list container.

Following are the conditions:

If n is smaller than the current container size then the list container is reduced to n elements, removing all the elements that extends the n space.

If n is greater than the current container size then the size of the container is increased and more elements can be inserted in the expanded space.

Syntax

void resize(size_type n, value_type val )

Parameter

n : It is a new container size.

< val : It is a value which is to be inserted in a newly constructed space.

Return value

It does not return any value.

Example 1

Let's see a simple example when n is less than the current container size.

#include <iostream>
#include<list>
using namespace std;
int main()
{
  list<int> li={1,2,3,4,5};
  list<int>::iterator itr;
  std::cout << "Content of list li :" << std::endl;
  for(itr=li.begin();itr!=li.end();++itr)
  cout<<*itr<<",";
  li.resize(3);
  cout<<'\n';
  std::cout << "After resizing,Content of list li :" << std::endl;
  for(itr=li.begin();itr!=li.end();++itr)
   cout<<*itr<<",";
    return 0;
}

Output:

Content of list li :
1,2,3,4,5
Content of list li :
1,2,3

In this example, resize function decreases the size of the list container by 2. Therefore, the last two elements of the list has been removed and output becomes 1,2,3.

Example 2

Let's see a simple example when n is greater than the current container size.

#include <iostream>
#include<list>
using namespace std;
int main()
{
  list<int> li={10,20,30,40};
  list<int>::iterator itr;
  std::cout << "Content of list li :" << std::endl;
  for(itr=li.begin();itr!=li.end();++itr)
  cout<<*itr<<",";
  li.resize(7,50);
  cout<<'\n';
  std::cout << "After resizing,Content of list li :" << std::endl;
  for(itr=li.begin();itr!=li.end();++itr)
   cout<<*itr<<",";
    return 0;
}

Output:

Content of list li :
10,20,30,40
After resizing,Content of list li :
10,20,30,40,50,50,50

In this example, resize function increases the size of the list by 3 and the new element i.e 50 is inserted in a newly constructed space.