#include <cstdio>
#include <cstring>
#include <malloc.h>
#include <assert.h>

const size_t mem_size = 16L * 1024*1024*1024;
const size_t block_size = 20 * 1024 * 1024;
const size_t blocks_count = (mem_size / block_size) / 2;

int main() {
    void* p;
    /*{
        p = malloc(block_size);
        free(p);
    }*/

    printf("Allocate 1/2 of the main memory\n");
    void** blocks = new void*[blocks_count];
    for (size_t i = 0; i < blocks_count; ++i) {
        blocks[i] = malloc(block_size);
        memset(blocks[i], 0, block_size);
    }

    printf("Free 1/4 of the main memory\n");
    for (size_t i = 0; i < blocks_count; i+=2)
        free(blocks[i]);

    printf("Allocate big array (1/2 of the main memory)\n");
    p = malloc(mem_size / 2);
    printf("Initialize big array\n");
    memset(p, 0, mem_size / 2);
    printf("OK\n");

    free(p);
    delete [] blocks;
    return 0;
}