C++day4

#include 
#include 

using namespace std;

class myString{
private:
    //string
    char *str;//字符串
    int size;//字符串长度
public:
    //无参构造
    myString();
    //有参构造
    myString(const char *s);
    //拷贝构造
    myString(myString &other);
    //析构函数
    ~myString();
    //判空函数
    bool myEmpty();
    //size函数
    size_t mySize();
    //c_str函数
    char* myC_str();
    //at函数
    char myAt(int pos);
    //为字符串赋值
    const myString & operator=(const myString &C){
        delete []str;
        this->size = C.size;
        this->str = new char[size+1];
        strcpy(this->str,C.str);
        cout<<"为字符串赋值函数"< size)
            cout<<"越界"<size += C.size;
        strcat(this->str, C.str);
        cout<<"链接字符函数"<str == C.str && this->size == C.size)
            return true;
        else
            return false;
    }
    //比较字符串大于
    bool operator>(const myString &C)const{
        if(this->str > C.str)
            return true;
        else
            return false;
    }
    //比较字符串小于
    bool operator<(const myString &C)const{
        if(this->str < C.str)
            return true;
        else
            return false;
    }
    //输入
    friend istream & operator>>(istream &cin, myString &C );
    //输出
    friend ostream & operator<<(ostream &cout, myString &C);
    //展示string
    void show(){
        cout<str< size)
        cout<<"越界"<>(istream &cin, myString &C ){
    string s;
    cin>>s;
    delete []C.str;
    strcpy(C.str, s.c_str());
    C.size = s.size();
    return cin;
}
//输出
ostream & operator<<(ostream &cout, myString &C){
    return cout< s1)
        cout<<"s3 > s1"< s1"<>s4;
    s4.show();
    //输出
    cout<