[2018年6月1号]C++ primer 课后练习 第十六章 模版与泛型编程

16.26

用函数指针来实现删除器,想不出来时候多睡一会

template *>
class my_shared_ptr {
public:
    my_shared_ptr(Func func = 0) :data(nullptr), useCount(new int(1)),del(a) {

    }
    my_shared_ptr(T* value, Func func = 0):data(value), useCount(new int(1)), del(func) {
        
    }
    my_shared_ptr(const my_shared_ptr& msp, Func func = 0):data(msp.data),use_count(msp.useCount), del(func) {
        if(*useCount){
            ++*useCount;
        }
    }
    my_shared_ptr& operator=(const my_shared_ptr& msp){
        if(--*useCount == 0){
            delete data;
            delete useCount;
        }
        data = msp.data;
        useCount = msp.useCount;
        ++*useCount;
        return *this;
    }
    size_t use_count(){
        return use_count;
    }
    T* get() {
        return data;
    }
    void swap(my_shared_ptr& msp){
        std::swap(this->data, msp.data);
    }
    void reset(my_shared_ptr& data){
        free();
        this->data = data.data;
        this->useCount = data.useCount;
        ++*data.use_count;
    }
    bool unique(){
        if(*useCount == 1){
            return true;
        }
        return false;
    }
    T& operator*() { return *p; }
    T& operator*() const { return *p; }
    ~my_shared_ptr(){
        free();
    }
private:
    void free(){
        if (--*useCount == 0) {
            cout << del << endl;
            del ? (*del)(data) : delete data;
        }
    }
    T* data;
    int* useCount;
    Func del = 0;
};

unique_ptr类同

template *>
class my_unique_ptr {
public:
    my_unique_ptr(T* data, Func func = 0): data(data), del(func){}
    T* release(){
        T* tmpData = data;
        data = 0;
        return tmpData;
    }
    void reset(){
        data = 0;
    }
    void reset(T* p){
        delete data;
        data = p;
    }
    ~my_unique_ptr(){
        del ? (*del)(data) : delete data;
    }
private:
    T*  data;
    Func del = 0;
};

16.29

略

16.30

略

16.31

将DebugDelete()作为函数指针传入,判断当前是否存在该指针来判断是否使用删除器

16.32