vector::reserve

Reserves a minimum length of storage for a vector object, allocating space if necessary.

void reserve( 
   size_type _Count 
);

Parameters

  • _Count
    The minimum length of storage to be allocated for the vector.

Example

// vector_reserve.cpp
// compile with: /EHsc
#include <vector>
#include <iostream>

int main( )
{
   using namespace std;   
   vector<int> v1;
   
   v1.push_back(1);
   cout << "Current capacity of v1 = " 
      << v1.capacity( ) << endl;
   v1.reserve(20);
   cout << "Current capacity of v1 = " 
      << v1.capacity( ) << endl;
}
Current capacity of v1 = 1
Current capacity of v1 = 20

Requirements

Header: <vector>

Namespace: std

See Also

Reference

vector Class

Standard Template Library