Reserve Speeds

#include <iostream>
#include <time.h>
#include <vector>

using namespace std;

int main()
{
    clock_t t1;
    clock_t t2;

    t1 = clock();
    for( int t = 0; t < 1000; t++ )
    {
        vector<int> a;
        a.reserve(100000);
        for( int i = 0; i < 100000; i++ )
            a.push_back(i);
    }
    t2 = clock();

    cout << (t2-t1) / (double)CLOCKS_PER_SEC << endl;

    t1 = clock();
    for( int t = 0; t < 1000; t++ )
    {
        vector<int> a;
        for( int i = 0; i < 100000; i++ )
            a.push_back(i);
    }
    t2 = clock();

    cout << (t2-t1) / (double)CLOCKS_PER_SEC << endl;

    return 0;
}

/*

TESTED OUTPUT:

(with -O3)
0.27953
0.599311

(default)
1.56081
1.9982

*/