C++: day4

1.封装mystring类

#include 
#include 

using namespace std;

class Mystring
{
private:
    char *str;      //记录c风格字符串
    int sizes;       //记录字符串的实际长度

public:
    Mystring():sizes(10)      //无参构造
    {
        str = new char[sizes];       //默认设置10字节
        strcpy(str, "");        //初始化为空串
    }

    Mystring(const char *s)     //有参构造
    {
        sizes = strlen(s);       //字符串长度
        str = new char[sizes+1];     //最后\0算上
        strcpy(str, s);     //字符串复制
    }

    ~Mystring()     //析构函数
    {
        delete []str;       //释放指针指向空间
    }

    Mystring (const Mystring &other)        //拷贝构造函数
    {
        sizes = other.sizes;
        str = new char[sizes+1];
        strcpy(str, other.str);
    }

    Mystring &operator=(const Mystring &other)      //拷贝赋值函数
    {
        delete this;
        sizes = other.sizes;
        this->str = new char[sizes+1];
        strcpy(str, other.str);

        return *this;
    }

    bool empty()        //判空函数
    {
        if (sizes == 0)
            return true;
        else
            return false;
    }

    int size()      //size函数
    {
        return sizes;
    }

    const char *c_str()       //c_str函数
    {
        return str;
    }

    char &at(int pos)       //at()函数
    {
        if(pos >= sizes || pos < 0)
        {
            cout << "下标不合法" <sizes + R.sizes;
        temp.str = new char[temp.size];
        
        temp.str = strcat(this->str, R.str);
      
        return temp;
    }

    Mystring &operator+=(const Mystring &R)      //成员函数实现+=
    {
        strcat(this->str, R.str);
        this->sizes = this->sizes + R.sizes;

        return *this;
    }

    bool operator>(const Mystring &R)const      //成员函数实现>
    {
        if(strcmp(this->str, R.str))
        {
            return true;
        }
        else
        {
            return false;
        }
    }
};



int main()
{
    Mystring s1;        //无参构造
    Mystring s2("hello");       //有参构造
    s1 = s2;       //拷贝赋值函数
    //        Mystring s1 = s2;        //拷贝构造函数
//    Mystring s1;
    s1 += s2;


    if (s1.empty())     //判空
        cout << "空" < s2" <

 2.思维导图