vector_realloc.cpp

/*
* Copyright (C) 2012, Tino Didriksen Consult
* Developed by Tino Didriksen <tino@didriksen.cc>
* Modified by Massimo Ronca
*
* This file is part of Benchmarks
*
* Benchmarks is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Benchmarks is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Benchmarks.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <cstdlib>
#include <iostream>
#include <vector>

int main() {
    int *c = (int*)malloc(sizeof(*c));
    int *old_c = c;
    size_t c_cap = 1;
    size_t cnt_c = 0;

    std::vector<int> v(1);
    int *old_v = &v[0];
    size_t cnt_v = 0;

    for (size_t i=0 ; i<10000000 ; ++i) {
        if(i == c_cap) {
            c_cap *= 2;
            c = (int*)realloc(c, sizeof(*c)*c_cap);
            if (old_c != c) {
                ++cnt_c;
            }
            old_c = c;
        }
        c[i] = i;


        v.push_back(i);

        if (old_v != &v[0]) {
            ++cnt_v;
        }
        old_v = &v[0];
    }

    std::cout << "realloc() reallocations: " << cnt_c << std::endl;
    std::cout << "std::vector reallocations: " << cnt_v << std::endl;

    free(c);
}