思维导图

代码

#include <iostream>
#include<string.h>

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
    }
    //有参构造
    myString(const char *s)          //string  s("hello world")
    {
        size = strlen(s);
        str = new char[size+1];
        strcpy(str, s);
    }
    //拷贝构造
    myString(const myString &other):str(other.str), size(other.size)
    {
        str = new char[size+1];
        strcpy(str, other.str);
        size = other.size;
        cout<<"拷贝构造"<<endl;
    }
    //析构函数
    ~myString()
    {
        delete str;
        cout<<"~"<<endl;
    }
    //拷贝赋值函数
    myString& operator=(const myString& other)
    {
        if(this != &other)          //确定不是自己给自己赋值
        {
            this->size = other.size;
            //判断原来指针空间释放被清空
            if(this->str != NULL)
            {
                delete this->str;
            }
            this->str = new char(*other.str);
        }
        cout<<"Stu:: 拷贝赋值函数"<<endl;
        return  *this;             //返回自身引用
    }
    //判空函数
    bool isEmpty()
    {
        return size==0;
    }
    //size函数
    int Size()
    {
        return strlen(str);
    }
    //c_str函数
    char* c_str()
    {
        return str;
    }
    //at函数
    char &at(int pos)
    {
        if(pos > size-1)
        {
            cout<<"下标超出范围";
        }else{
            return str[pos];
        }
    }
    //加号运算符重载
    const myString operator+(const myString& other)const
    {
        myString temp;
        temp.size = this->size + other.size;
        strcpy(temp.str, this->str);
        strcat(temp.str, other.str);
        return temp;
    }
    //加等于运算符重载
    myString& operator+=(const myString& other)
    {
        strcat(this->str, other.str);
        this->size += other.size;
        return *this;
    }
    //关系运算符重载（>）
    bool operator>(const myString& other)const
    {
        int j = strlen(str);
        for(int i=0; i<j; i++)
        {
            if(str[i]>other.str[i])
            {
                return true;
            }else
            {
                return false;
            }
        }
    }
    //中括号运算符重载
    char & operator[] (int pos)
    {
        if(pos > size-1)
        {
            cout<<"下标超出范围";
        }else{
            return str[pos];
        }
    }
};
int main()
{
    myString s1("hello");
    myString s2(" world");
    cout<<s1.c_str()<<endl;
    cout<<s1.at(4)<<endl;
    cout<<s1.Size()<<endl;
    myString s3 = s1;
    cout<<s3.c_str()<<endl;
    s3+=s2;
    cout<<s3.c_str()<<endl;
    cout<<s3[10]<<endl;
    myString s4;
    s4 = s3;
    if(s1>s2)
    {
        cout<<"yes"<<endl;
    }else
    {
        cout<<"no"<<endl;
    }
    return 0;
}

运行截图