8月24日C++作业

 

#include <iostream>
#include <cstring>

using namespace std;
class my_string
{
private:
    char *str;
    int len;
public:
    friend ostream& operator<<(ostream& L, const my_string& o);
    my_string():str(NULL)
    {
        cout<<"这是一个无参构造函数"<<endl;
    }
    my_string(char *str, int len)
    {
        this->str = str;
        this->len = len;
        cout<<"这是一个有参构造函数"<<endl;
    }
    ~my_string()
    {
        delete str;
        str = NULL;
        cout<<"这是一个析构函数"<<endl;
    }
    my_string(const my_string& other)
    {
        this->len = other.len;
        this->str = new char[other.len+1];
        char *p = this->str;
        char *q = other.str;
        int i = 0;
        for(i=0; i<len; i++)
        {
           *(p++) = *(q++);
        }
         cout<<"这是一个深拷贝构造函数"<<endl;
    }
    my_string& operator=(const my_string& other)
    {
        if(&other != this)
        {
            this->len = other.len;

            if(this->str != NULL)
            {
                delete []this->str;
                this->str = NULL;
            }
            this->str = new char[len+1];
            int i = 0;
            char *p = this->str;
            char *q = other.str;
            for(i=0; i<len; i++)
            {
               *(p++) = *(q++);
            }
        }
        cout<<"这是一个深拷贝赋值函数"<<endl;
        return *this;
    }
    my_string operator+(const my_string& a)const
    {
        my_string temp;
        temp.len = this->len + a.len;
        temp.str = new char[temp.len+1];
        strcpy(temp.str, this->str);
        strcat(temp.str, a.str);
        cout<<"这是一个+运算符重载函数"<<endl;
        return temp;
    }
    char operator[](int n)
    {
        cout<<"这是一个[]运算符重载函数"<<endl;
        return this->str[n];
    }
    char* show()
    {
       return str;
    }
    bool my_empty()
    {
        if(str == NULL)
            return false;
        else
            return true;
    }
    int my_size()
    {
        return len;
    }
};
ostream& operator<<(ostream& L, const my_string& o)
{
    L<<o.str<<"  "<<o.len;
    cout<<"这是一个插入运算符重载函数";
    return L;
}
int main()
{
//    my_string stu1("cdq",3);
//    cout<<stu1.show()<<endl;
//    my_string stu2(stu1);
//    cout<<stu2.show()<<endl;
//    my_string stu3;
//    stu3 = stu2;
//    cout<<stu3.show()<<endl;
//    cout<<stu3.my_empty()<<endl;
//    cout<<stu3.my_size()<<endl;
    my_string s1("cdq", 3);
    my_string s2("zjf", 3);
    my_string s3 = s1 + s2;
    cout<<s3.show()<<endl;
    cout<<s3<<endl;
    cout<<s3[2]<<endl;





}