Demonstrate how vector<bool> uses much less space than one byte per entry

vec.cc

// * compile without optimization
// * run an inferior shell
// * type limit -d 2048 to restrict the data segment to 2 megs
// * ./a.out
// * profit!

#include <sys/resource.h>

#include <cstdint>
#include <iostream>
#include <memory>
#include <vector>

using namespace std;

template<typename T>
unsigned long countem() {
  unique_ptr<vector<T>> vp(new vector<T>);
  unsigned long high = 0;
  while (++high) {
    try {
      vp->push_back(0);
    }
    catch (bad_alloc& ba) {
      return high;
    }
  }
}

int main(int argc, char* argv[]) {
  rlimit rlim;
  getrlimit(RLIMIT_DATA, &rlim);
  unsigned long dlimit = rlim.rlim_cur;
  cout << "RLIMIT_DATA " << dlimit << endl;
  cout << "uint64_t " << countem<uint64_t>() << endl;
  cout << "uint8_t " << countem<uint8_t>() << endl;
  cout << "bool " << countem<bool>() << endl;
}