C++ day4

1、仿照string类，完成myString 类

#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

    }

    //有参构造

    myString(const char *s)

    {

        size = strlen(s);

        str = new char[size+1];

        strcpy(str, s);

    }

    //拷贝构造函数

    myString(const myString &other):str(new char(*(other.str))),size(other.size)

    {

        strcpy(this->str,other.str);    //拷贝字符串

        this->size = other.size;    //拷贝字符串长度

        cout<<"myString::拷贝构造函数 str = "<    }

    //析构函数

    ~myString()

    {

        delete str;

        cout<<"myString::析构函数 this = "< 
    }
 
 
 
    //拷贝赋值函数
 
    myString & operator=(const myString &other)
 
    {
 
        if(this != &other)
 
        {
 
            strcpy(this->str, other.str);
 
            this->size = other.size;
 
        }
 
        cout<<"myString::拷贝赋值函数 str = "<        return *this;
 
    }
 
 
    //判空函数
 
    bool empty()
 
    {
 
        return 0==size;
 
    }
 
 
    //size函数
 
    int myString_size()
 
    {
 
        return strlen(str);
 
    }
 
 
    //c_str函数
 
    const char *c_str()
 
    {
 
        return this->str;
 
    }
 
 
    //at函数
 
    char &at(int pos)
 
    {
 
        return str[pos-1];
 
    }
 
 
    //加号运算符重载
 
   const myString operator+(const myString &str)const
 
    {
 
        myString temp;
 
        temp.size = this->size+str.size;
 
        temp.str = strcat(temp.str, this->str);
 
        temp.str = strcat(temp.str, str.str);
 
        return temp;
 
    }
 
 
    //加等于运算符重载
 
    const myString operator+=(const myString &str)
 
    {
 
        strcat(this->str, str.str);
 
        this->size = strlen(this->str);
 
        return *this;
 
    }
 
 
 
    //关系运算符重载
 
 
    bool operator >(const myString &s)const{
 
        if(this->size < s.size){
 
            return false;
 
        }
 
        else{
 
            for(int i=0;isize;i++){
 
                if(*(this->str+i)<*(s.str+i)){
 
                    return false;
 
                }
 
            }
 
        }
 
        return true;
 
}
 
 
 
    //中括号运算符重载
 
    char & operator[](const int pos)const{
 
        if(pos>=size || pos<0){
 
            cout<<"访问越界"< 
        }
 
        return *(str+pos);
 
    }
 
};
 
 
int main()
 
{
 
    myString s1("hello world");
 
 
    myString s2(s1);
 
 
    myString s3;
 
    s3 = s2;
 
    cout << "字符串长度为：" < 
 
    cout<<"at(1) = "< 
 
    cout<<"c_str: "< 
 
 
    return 0;
 
}
 
 
2、思维导图