【C++】day4学习成果：仿写string类等等

1.仿照string类，完成myString 类
代码：

#include 
#include 

using namespace std;

class myString
{
    private:
        char *str;          //记录c风格的字符串
        int size;            //记录字符串的实际长度
    public:
        //无参构造
        myString():size(10)
        {
            str = new char[size];         //构造出一个长度为10的字符串
            strcpy(str,"");         //赋值为空串
            cout<<"无参构造"<<endl;
        }
        //有参构造
        myString(const char *s)          //string  s("hello world")
        {
            size = strlen(s);
             str = new char[size+1];
             strcpy(str, s);
             cout<<"有参构造"<<endl;
        }

        //拷贝构造
        myString(const myString &other):
            str(new char(*other.str)),size(other.size)
        {
//            strcpy(str,"");         //赋值为空串
//            for(int i=0;isize;i++)
//            {
//                str[i]=this->str[i];
//            }
            cout<<"拷贝构造成功"<<endl;
        }
        //析构函数
        ~myString()
        {
            delete str;
            str=nullptr;
        }
        //拷贝赋值函数
        myString & operator=(const myString &other)
        {
            if(this!=&other)
            {
                this->size=other.size;
                if(this->str!=NULL)
                {
                    delete this->str;
                }
                this->str=new char(*other.str);
            }
            cout<<"拷贝赋值成功"<<endl;
            return *this;
        }
        //判空函数
        bool empty()
        {
            if(strcmp(str,"")==0)
            {
                return true;
            }else {
                return false;
            }
        }
        //size函数
        int s_size()
        {
            return strlen(this->str);
        }
        //c_str函数:返回字符串的首地址
        char *c_str()
        {
            return str;
        }
        //at函数
        char &at(int pos)
        {
            return str[pos];
        }
        //加号运算符重载
        const myString operator+(myString &s)const
        {
            myString c;
            c.size=this->size+s.s_size();
            c.str=this->str;
            strcat(c.str,s.str);
            return c;
        }
        //加等于运算符重载
        myString & operator+=(const myString &s)
        {
            this->size+=s.size;
            strcat(this->str,s.str);
            return  *this;
        }
        //关系运算符重载（>）
        bool operator>(const myString &s)const
        {
            if(strcmp(this->str,s.str)>0)
            {
                return true;
            }else {
                return false;
            }
        }
        //中括号运算符重载
        char & operator[](int index)
        {
            return this->str[index];
        }

        //查看函数
        void show()
        {
            cout<<"size="<<size<<endl;
            cout<<"s_size="<<s_size()<<endl;
            cout<<"str="<<str<<endl;
        }
};

int main()
{
    myString s1("hello");
    s1.show();

    myString s2(" world");
    s2.show();

    myString s3=s1+s2;
    s3.show();

    if(s1>s2)
    {
        cout<<"yes"<<endl;
    }else{ cout<<"no"<<endl; }

    return 0;
}

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运行结果：

2.思维导图