思维导图

作业：

仿照string类，实现myString

代码

mystring.h

#ifndef MYSTRING_H
#define MYSTRING_H

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

using namespace std;

class myString
{
private:
    char *str;
    int  size;

public:
    //无参构造
    myString():size(10)
    {
        str = new char[size];
    }

    //有参构造
    myString(const char *s);

    //判空函数
    void judge_empty();

    //size函数
    int str_size ();

    //c_str函数
    const char *c_str();

    //at函数
    char &at (int index);

    //二倍扩容
    void expend();

    //析构函数
    ~myString()
    {
        delete []this->str;
        cout << "析构成功" << endl;

    }
};

#endif // MYSTRING_H

mystring.cpp

#include"mystring.h"

//有参构造
myString::myString(const char *s)
{
    size = strlen(s);
    this->str = new char [size+1];
    strcpy(this->str , s);
    cout <<"s1 : "<<this->str<<endl;
}

//判空函数
void myString::judge_empty()
{
    if(!*(this->str))
    {
        cout << "空" <<endl;
    }
    else
     {
         cout << "非空" <<endl;
    }
}

//size函数
int myString::str_size ()
{
    return this->size;
}

//c_str函数
const char *myString::c_str()
{
   return this->str;
}

//at函数
char &myString::at (int index)
{
   return  str[index];
}

//二倍扩容
void myString::expend()
{
    size*=2;
    char *temp=new char[size];
    strcpy(temp,this->str);
    delete[]this->str;
    this->str=temp;
}

main.cpp

#include "mystring.h"

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

    cout <<"size="<<s1.str_size()<<endl;

    cout<<"第1个字符为"<<s1.at(0)<<endl;

    cout << "s1判空结果为：";
    s1.judge_empty();

    return 0;
}

结果