In file included from main.cpp:28:0:
fixed_allocator.h:3:7: error: redefinition of 'class PageAllocator'
 class PageAllocator {
       ^~~~~~~~~~~~~
main.cpp:4:7: note: previous definition of 'class PageAllocator'
 class PageAllocator {
       ^~~~~~~~~~~~~
In file included from main.cpp:28:0:
fixed_allocator.h: In instantiation of 'FixedAllocator<Tp>::FixedAllocator(uint64_t) [with Tp = int; uint64_t = long unsigned int]':
main.cpp:44:32:   required from here
fixed_allocator.h:15:75: error: no matching function for call to 'PageAllocator::PageAllocator()'
     explicit FixedAllocator(std::uint64_t page_size) : page_size(page_size) {}
                                                                           ^
main.cpp:9:5: note: candidate: PageAllocator::PageAllocator(uint64_t)
     PageAllocator(std::uint64_t page_size) : page_size_(page_size) {
     ^~~~~~~~~~~~~
main.cpp:9:5: note:   candidate expects 1 argument, 0 provided
main.cpp:4:7: note: candidate: PageAllocator::PageAllocator(const PageAllocator&)
 class PageAllocator {
       ^~~~~~~~~~~~~
main.cpp:4:7: note:   candidate expects 1 argument, 0 provided
In file included from main.cpp:28:0:
fixed_allocator.h: In instantiation of 'Tp* FixedAllocator<Tp>::Allocate() [with Tp = int]':
main.cpp:45:30:   required from here
fixed_allocator.h:19:15: error: cannot convert 'char*' to 'int*' in assignment
             p = new char[sizeof(Tp) * page_size];
             ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fixed_allocator.h: In instantiation of 'FixedAllocator<Tp>::FixedAllocator(uint64_t) [with Tp = std::__cxx11::basic_string<char>; uint64_t = long unsigned int]':
main.cpp:55:41:   required from here
fixed_allocator.h:15:75: error: no matching function for call to 'PageAllocator::PageAllocator()'
     explicit FixedAllocator(std::uint64_t page_size) : page_size(page_size) {}
                                                                           ^
main.cpp:9:5: note: candidate: PageAllocator::PageAllocator(uint64_t)
     PageAllocator(std::uint64_t page_size) : page_size_(page_size) {
     ^~~~~~~~~~~~~
main.cpp:9:5: note:   candidate expects 1 argument, 0 provided
main.cpp:4:7: note: candidate: PageAllocator::PageAllocator(const PageAllocator&)
 class PageAllocator {
       ^~~~~~~~~~~~~
main.cpp:4:7: note:   candidate expects 1 argument, 0 provided
In file included from main.cpp:28:0:
fixed_allocator.h: In instantiation of 'Tp* FixedAllocator<Tp>::Allocate() [with Tp = std::__cxx11::basic_string<char>]':
main.cpp:57:24:   required from here
fixed_allocator.h:19:15: error: cannot convert 'char*' to 'std::__cxx11::basic_string<char>*' in assignment
             p = new char[sizeof(Tp) * page_size];
             ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fixed_allocator.h: In instantiation of 'FixedAllocator<Tp>::FixedAllocator(uint64_t) [with Tp = char; uint64_t = long unsigned int]':
main.cpp:116:35:   required from here
fixed_allocator.h:15:75: error: no matching function for call to 'PageAllocator::PageAllocator()'
     explicit FixedAllocator(std::uint64_t page_size) : page_size(page_size) {}
                                                                           ^
main.cpp:9:5: note: candidate: PageAllocator::PageAllocator(uint64_t)
     PageAllocator(std::uint64_t page_size) : page_size_(page_size) {
     ^~~~~~~~~~~~~
main.cpp:9:5: note:   candidate expects 1 argument, 0 provided
main.cpp:4:7: note: candidate: PageAllocator::PageAllocator(const PageAllocator&)
 class PageAllocator {
       ^~~~~~~~~~~~~
main.cpp:4:7: note:   candidate expects 1 argument, 0 provided