Ubuntu – C++ header files changes program break

I can’t understand why this code prints different program breaks

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <ftw.h>
#include <stdlib.h>

int main()
{
    int max_size = 1024;
    char* ptr[max_size];

    int blockCount = 1000;
    int blockSize = 4*1024*1024;
    int from = 1;
    int to = blockCount;
    int step = 1;
    int i;

    printf("Program break: 0x%pn", sbrk(0));
    for(i = 0; i < blockCount; ++i)
    {
        ptr[i] = (char*)malloc(blockSize);
    }

    printf("Program break: 0x%pn", sbrk(0));
    for(int i = from; i < to; i += step)
    {
        free((char*)ptr[i]);
    }

    printf("Program break: 0x%pn", sbrk(0));
}

The output:

Program break: 0x0x5604211f1000
Program break: 0x0x560421212000
Program break: 0x0x560421212000

But if I prepend an #include <iostream> at the beginning of the file it prints the same program break.

The output:

Program break: 0x0x556617053000
Program break: 0x0x556617053000
Program break: 0x0x556617053000

Does it change the program break in headers ?
If so what can possibly change the program break in a header file ?
Also if compiled as a C code the last program break points to the initial. As if free returns the pages which are not used.
But in C++ case it doesn’t happen.

g++ version: 9.4.0

Compile options: -O0

OS/ABI: UNIX – System V

ABI Version: 0

Kernel version: 5.15.0-87-generic

Distro: Ubuntu 20.04.6 LTS