移动语义影响智能指针，std::move转移示例解析

#include 
#include 

struct MyClass {
    int value;
    MyClass(int v) : value(v) { std::cout << "构造: " << value << "\n"; }
    ~MyClass() { std::cout << "析构: " << value << "\n"; }
};

int main() {
    std::unique_ptr ptr1 = std::make_unique(42);
    std::cout << "ptr1 value: " << ptr1->value << "\n";

    // 使用std::move转移所有权
    std::unique_ptr ptr2 = std::move(ptr1);

    // 此时ptr1为空，ptr2持有对象
    if (ptr1 == nullptr) {
        std::cout << "ptr1 已为空\n";
    }
    std::cout << "ptr2 value: " << ptr2->value << "\n";

    return 0;
}

#include 
#include 

int main() {
    std::shared_ptr sp1 = std::make_shared(100);
    std::cout << "sp1 use_count: " << sp1.use_count() << "\n";

    // 移动sp1到sp2
    std::shared_ptr sp2 = std::move(sp1);

    std::cout << "移动后 sp1 use_count: " << (sp1 ? "非空" : "空") << "\n";
    std::cout << "sp2 use_count: " << sp2.use_count() << ", value: " << *sp2 << "\n";

    return 0;
}

void process_ptr(std::unique_ptr ptr) {
    std::cout << "处理对象: " << ptr->value << "\n";
} // ptr在此处析构

int main() {
    auto p = std::make_unique(99);
    process_ptr(std::move(p)); // 所有权转移给函数

    if (!p) {
        std::cout << "p 已移交\n";
    }
    return 0;
}