mz06-3

#include <cstdio>

class FileWrapper {
    struct FileCount {
        FILE *fd = nullptr;
        unsigned int count = 0;

        FileCount(FILE *pfd) : fd(pfd), count(1) {}
    };

    FileCount *fileCount = nullptr;

    void setFileCount(FileCount *newFileCount) {
        if (fileCount != nullptr) {
            --(fileCount->count);
            if (fileCount->count == 0) {
                fclose(fileCount->fd);
                delete fileCount;
            }
        }

        fileCount = newFileCount;
        if (fileCount != nullptr) {
            ++(fileCount->count);
        }
    }

    void swap(FileWrapper& other) noexcept {
        FileCount* tmp = other.fileCount;
        other.fileCount = fileCount;
        fileCount = tmp;
    }
public:
    FileWrapper(const char *path) {
        FILE *fd = fopen(path, "w");
        fileCount = new FileCount(fd);
    }

    FileWrapper(const FileWrapper &fileWrapper) : fileCount(fileWrapper.fileCount) {
        ++(fileCount->count);
    }

    FileWrapper(const FileWrapper &&fileWrapper) : fileCount(fileWrapper.fileCount) {
        ++(fileCount->count);
    }

    FileWrapper& operator=(const FileWrapper &fileWrapper) {
        if (this == &fileWrapper) {
            return *this;
        }
        FileWrapper(fileWrapper).swap(*this);
        return *this;
    }

    FileWrapper& operator=(const FileWrapper &&fileWrapper) {
        if (this == &fileWrapper) {
            return *this;
        }
        FileWrapper(fileWrapper).swap(*this);
        return *this;
    }

    FileWrapper& operator<<(char ch) {
        fputc(ch, fileCount->fd);
        return *this;
    }

    ~FileWrapper() {
        setFileCount(nullptr);
    }
};