>>600　C++ Windows

#include <Windows.h>
#include <iostream>

int main()
{
auto drives = GetLogicalDrives();
for (int i = 0; i < 32; ++i) {
if (drives & (1 << i)) {
char directory[] = "A:";
directory[0] += i;
ULARGE_INTEGER freeBytes;
if (GetDiskFreeSpaceExA(directory, nullptr, nullptr, &freeBytes) != 0) {
std::cout << directory << " " << freeBytes.QuadPart << std::endl;
}
}
}
}