C++ Vector Library - vector() Function

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Description

The C++ fill constructor std::vector::vector() constructs a container of size n and assigns value val(if provided) to each element of the container.

Declaration

Following is the declaration for fill constructor std::vector::vector() form std::vector header.

C++98

explicit vector (size_type n, const value_type& val = value_type(), 
   const allocator_type& alloc = allocator_type());

C++11

vector (size_type n, const value_type& val,
   const allocator_type& alloc = allocator_type());
      explicit vector (size_type n);

Parameters

• n − Size of container.

• val − Value to be assigned to each element of container.

Return value

Constructor never returns value.

Exceptions

This member function never throws exception.

Time complexity

Linear i.e. O(n)

Example

The following example shows the usage of fill constructor std::vector::vector().

#include <iostream>
#include <vector>

using namespace std;

int main(void) {
   vector<int> v(5, 200);

   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 −

200
200
200
200
200