一点基础知识

来源：互联网发布：日语零基础自学知乎编辑：程序博客网时间：2024/04/29 18:38

这里有sizeof，c++类的静态成员变量；再就是虚函数，以及申明的问题，字节长度的问题。

#include <iostream>#include <string>using namespace std;class State{public:    State(){}    ~State(){;}    State(const int sta, const int depth)    {        //count ++;        this->sta = sta;        this->depth = depth;    }    int SetDepth(const int depth)    {        this->depth = depth;    }    //virtual int getDepth() = 0;    /*    virtual int getDepth()    {        return depth;    }    */    int getState()    {        return sta;    }    static int count;private:    int sta;    int depth;};int State::count = 0; // init; if not , it comes errorint main(int argc, char *argv[]){    State state(12, 3);    cout << "count " << state.count << endl;    state.count = 12;    cout << "count " << state.count << endl;    cout << state.getState() << endl;    cout << "size of int " << sizeof(int) << endl;    cout << "size of State " << sizeof(State) << endl;    string str("hello world");    cout << str << endl;    return 0;}

记住类的静态成员需要初始化；相应的输出结果是：

count 0count 1212size of int 4size of State 8hello world

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