{"id":420,"date":"2023-02-25T11:37:16","date_gmt":"2023-02-25T03:37:16","guid":{"rendered":"https:\/\/www.appblog.cn\/?p=420"},"modified":"2023-04-29T21:25:55","modified_gmt":"2023-04-29T13:25:55","slug":"android-ndk-basic-cpp-class-size-friend-function-operator-overloading","status":"publish","type":"post","link":"https:\/\/www.appblog.cn\/index.php\/2023\/02\/25\/android-ndk-basic-cpp-class-size-friend-function-operator-overloading\/","title":{"rendered":"Android NDK\u57fa\u784020\uff1aC++_\u7c7b\u5927\u5c0f_\u53cb\u5143\u51fd\u6570_\u8fd0\u7b97\u7b26\u91cd\u8f7d"},"content":{"rendered":"

\u7c7b\u5927\u5c0f<\/h2>\n
\/\/\u7c7b\u7684\u5927\u5c0f\nclass A {\npublic:\n    int i;\n    int j;\n    int k;\n    static int m;\n};\n\nclass B {\npublic:\n    int i;\n    int j;\n    int k;\n\n    void printf() {\n        cout << "\u6253\u5370" << endl;\n    }\n};\n\nvoid main() {\n    cout << sizeof(A) << endl;  \/\/12\n    cout << sizeof(B) << endl;  \/\/12\n\n    \/\/C\/C++ \u5185\u5b58\u5206\u533a\uff1a\u6808\u3001\u5806\u3001\u5168\u5c40\uff08\u9759\u6001\u3001\u5168\u5c40\uff09\u3001\u5e38\u91cf\u533a\uff08\u5b57\u7b26\u4e32\uff09\u3001\u7a0b\u5e8f\u4ee3\u7801\u533a\n    \/\/\u666e\u901a\u5c5e\u6027\u4e0e\u7ed3\u6784\u4f53\u76f8\u540c\u7684\u5185\u5b58\u5e03\u5c40\n\n    \/\/JVM \u5185\u5b58\u5206\u533a\uff1a\n    \/\/JVM Stack\uff08\u57fa\u672c\u6570\u636e\u7c7b\u578b\u3001\u5bf9\u8c61\u5f15\u7528\uff09\n    \/\/Native Method Stack\uff08\u672c\u5730\u65b9\u6cd5\u6808\uff09\n    \/\/\u65b9\u6cd5\u533a\n\n    system("pause");\n}<\/code><\/pre>\n
<\/p>\n
\u53cb\u5143\u51fd\u6570<\/h2>\n
\/\/\u53cb\u5143\u51fd\u6570\nclass A {\n    \/\/\u53cb\u5143\u51fd\u6570\n    friend void modify_i(A *p, int a);\nprivate:\n    int i;\npublic:\n    A(int i) {\n        this->i = i;\n    }\n\n    void print() {\n        cout << i << endl;\n    }\n};\n\n\/\/\u53cb\u5143\u51fd\u6570\u7684\u5b9e\u73b0\uff0c\u5728\u53cb\u5143\u51fd\u6570\u4e2d\u53ef\u4ee5\u8bbf\u95ee\u79c1\u6709\u7684\u5c5e\u6027\nvoid modify_i(A *p, int a) {\n    p->i = a;\n}\n\nvoid main() {\n    A* a = new A(10);\n    a->print();\n\n    modify_i(a, 20);\n    a->print();\n\n    system("pause");\n}<\/code><\/pre>\n
\/\/\u53cb\u5143\u7c7b\nclass A {        \n    \/\/\u53cb\u5143\u7c7b\n    friend class B;\nprivate:\n    int i;\npublic:\n    A(int i) {\n        this->i = i;\n    }\n\n    void print() {\n        cout << i << endl;\n    }    \n};\n\nclass B {\npublic:\n    \/\/B\u8fd9\u4e2a\u53cb\u5143\u7c7b\u53ef\u4ee5\u8bbf\u95eeA\u7c7b\u7684\u4efb\u4f55\u6210\u5458\n    void accessAny() {\n        a.i = 30;        \n    }\nprivate:\n    A a;\n};<\/code><\/pre>\n
\u8fd0\u7b97\u7b26\u91cd\u8f7d<\/h2>\n
\/\/\u8fd0\u7b97\u7b26\u91cd\u8f7d\nclass Point {\npublic:\n    int x;\n    int y;\npublic:\n    Point(int x = 0, int y = 0) {\n        this->x = x;\n        this->y = y;\n    }\n\n    void print() {\n        cout << x << "," << y << endl;\n    }\n};\n\n\/\/\u91cd\u8f7d+\u53f7\nPoint operator+(Point &p1, Point &p2) {\n    Point p(p1.x + p2.x, p1.y + p2.y);\n    return p;\n}\n\n\/\/\u91cd\u8f7d-\u53f7\nPoint operator-(Point &p1, Point &p2) {\n    Point p(p1.x - p2.x, p1.y - p2.y);\n    return p;\n}\n\nvoid main() {\n    Point p1(10, 20);\n    Point p2(20, 10);\n\n    Point p3 = p1 + p2;\n\n    p3.print();\n\n    system("pause");\n}<\/code><\/pre>\n
\/\/\u6210\u5458\u51fd\u6570\uff0c\u8fd0\u7b97\u7b26\u91cd\u8f7d\nclass Point {\npublic:\n    int x;\n    int y;\npublic:\n    Point(int x = 0, int y = 0) {\n        this->x = x;\n        this->y = y;\n    }\n\n    \/\/\u6210\u5458\u51fd\u6570\uff0c\u8fd0\u7b97\u7b26\u91cd\u8f7d\n    Point operator+(Point &p2) {\n        Point tmp(this->x + p2.x, this->y + p2.y);\n        return tmp;\n    }\n\n    void print() {\n        cout << x << "," << y << endl;\n    }\n};\n\nvoid main() {\n    Point p1(10, 20);\n    Point p2(20, 10);\n\n    \/\/\u8fd0\u7b97\u7b26\u7684\u91cd\u8f7d\uff0c\u672c\u8d28\u8fd8\u662f\u51fd\u6570\u8c03\u7528\n    \/\/p1.operator+(p2)\n    Point p3 = p1 + p2;\n\n    p3.print();\n\n    system("pause");\n}<\/code><\/pre>\n
\/\/\u5f53\u5c5e\u6027\u79c1\u6709\u65f6\uff0c\u901a\u8fc7\u53cb\u5143\u51fd\u6570\u5b8c\u6210\u8fd0\u7b97\u7b26\u91cd\u8f7d\nclass Point {\n    friend Point operator+(Point &p1, Point &p2);\nprivate:\n    int x;\n    int y;\npublic:\n    Point(int x = 0, int y = 0) {\n        this->x = x;\n        this->y = y;\n    }\n\n    void print() {\n        cout << x << "," << y << endl;\n    }\n};\n\nPoint operator+(Point &p1, Point &p2) {\n    Point p(p1.x + p2.x, p1.y + p2.y);\n    return p;\n}\n\nvoid main() {\n    Point p1(10, 20);\n    Point p2(20, 10);\n\n    \/\/\u8fd0\u7b97\u7b26\u7684\u91cd\u8f7d\uff0c\u672c\u8d28\u8fd8\u662f\u51fd\u6570\u8c03\u7528\n    \/\/p1.operator+(p2)\n    Point p3 = p1 + p2;\n\n    p3.print();\n\n    system("pause");\n}<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
\u7c7b\u5927\u5c0f \/\/\u7c7b\u7684\u5927\u5c0f class A { public: int i; int j; int k; stati […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11],"tags":[],"class_list":["post-420","post","type-post","status-publish","format-standard","hentry","category-android-ndk"],"_links":{"self":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/posts\/420","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/comments?post=420"}],"version-history":[{"count":0,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/posts\/420\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/media?parent=420"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/categories?post=420"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/tags?post=420"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}