C++ Vector Library - assign() Function

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Description

The C++ function std::vector::assign() assign new values to the vector elements by replacing old ones. It modifies size of vector if necessary.

If memory allocation happens allocation is allocated by internal allocator.

New contents are the copies of values passed as initializer list, in the same order.

Declaration

Following is the declaration for std::vector::assign() function form std::vector header.

C++11

void assign (initializer_list<value_type> ilist);

Parameters

ilist − Initializer list to assign values to vector.

Return value

None

Exceptions

This member function never throws exception.

Time complexity

Linear i.e. O(n)

Example

The following example shows the usage of std::vector::assign() function.

#include <iostream>
#include <vector>

using namespace std;

int main(void) {
   /* Create empty vector */
   vector<int> v;
   /* create initializer list */
   auto il = {1, 2, 3, 4, 5};

   /* assign values from initializer list */
   v.assign(il);

  /* display vector elements */
  for (int i = 0; i < v.size(); ++i)
      cout << v[i] << endl;

   return 0;
}

Let us compile and run the above program, this will produce the following result −

1
2
3
4
5