#include
using namespace std;
int main( )
{
// fill a vector with one million numbers the slow way
vector v1;
for( int i = 0; i < 1000000; ++i )
v1.push_back( i );
// fill a vector with one million numbers the fast way
vector v2; // has zero elements
v2.reserve( 1000000 ); // still has zero elements
for( int i = 0; i < 1000000; ++i )
v2.push_back( i );
}