use after delete

use_after_delete.cpp

#include <string>
#include <cstring>

class BrokenMemory {
public:
  static BrokenMemory *Get();
public:
  BrokenMemory() : data_("EPIC FAIL") {}
  const char *data() const { return data_.data(); }
private:
  static BrokenMemory *obj;
  std::string data_;
};

BrokenMemory *BrokenMemory::obj = NULL;
BrokenMemory *BrokenMemory::Get() {
  if(obj != NULL) {
    delete(obj);
    obj = NULL;
  }
  if(obj == NULL) {
    obj = new BrokenMemory();
  }
  return obj;
}

int main()
{
  BrokenMemory *before = BrokenMemory::Get();
  BrokenMemory *after = BrokenMemory::Get();
  printf("before\t:%s\n", before->data());
  printf("after\t:%s\n", after->data());
  return 0;
}