第3天作业 PoEdu MyString实现

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstring>

class MyString
{
    char *_str;
    int _len;
public:
    MyString()        
    {
        _str = new char[100];
        _len = 100;
    }
    MyString(const char *str)
    {
        if (str == NULL)
        {
            _str = new char[1];
            *_str = ‘\0‘;
        }
        else
        {
            int _len = strlen(str);
            _str = new char[_len + sizeof(char)];
            strcpy(_str, str);
        }
        
    }
    ~MyString()   
    {
        delete[]_str;
    }

    char *GetString()
    {
        return _str;
    }
    //设置字符串
    void SetString(const char *str)
    {
        delete[]_str;
        int _len = strlen(str);
        _str = new char[_len + sizeof(char)];
        strcpy(_str, str);                
    }

    //通过下标取得字符
    char GetChar(int index)
    {
        if(index<=strlen(_str) && index >= 0)
            return _str[index];
        return 0;
    }

    //求字符串长度
    unsigned int GetStringLens()
    {
        unsigned int index = 0;
        while (_str[index])
        {
            index++;
        }
        return index;
    }

    //求数组的长度
    unsigned int GetArryLens()
    {            
        return sizeof(_str) / sizeof(_str[0]);
    }

    //批量修改其中的某个字符为其它某个字符
    char * MyCharReplace(char dest,char source)
    {
        while (*_str!=‘\0‘)
        {
            if (*_str == dest)
            {
                *_str = source;
            }
            *_str++;
        }
        return _str;
    }

    //在末尾追加字符
    void MyAddEnd(char c)
    {
        char tmp[] = { c,‘\0‘ };
        MyString::MyAddEnd(tmp);
    };
    
    // 在末尾追加字符串
    void MyAddEnd(char *str)
    {
        _str = strncat(_str, str, strlen(str) + sizeof(char));
    }

    // 在末尾追加整数
    void MyAddEnd(int num)
    {
        char tmp[255]={0};
        sprintf(tmp,"%d",num);
        MyString::MyAddEnd(tmp);
    }

    //在末尾追加浮点数
    void MyAddEnd(double num)
    {
        char tmp[255] = { 0 };
        sprintf(tmp, "%8.3lf", num);
        MyString::MyAddEnd(tmp);
    }

    //在末尾追加MyString
    void MyAddEnd()
    {
        _str = strncat(_str, _str, strlen(_str) + sizeof(char));
    }

    //从头 弹出一个字符
    char PopupHead()
    {
        int index = 0;
        char tmp = _str[index];
        while(_str[index]!=0)
        {
            _str[index] = _str[index + 1];
            index++;
        }
        return tmp;
    }

    //从末尾弹出一个字符
    char PopupEnd()
    {
        int index = 0;
        while (_str[index] != 0)
        {            
            index++;
        }
        char tmp = _str[index-1];
        _str[index-1] = 0;
            
        return tmp;
    }
};



int main()
{
    MyString demo1("我爱你中国！");   //MyString demo2();

    MyString demo("I Love Mark");
    demo.SetString("i love HaoZaiYi");

    std::cout << demo.GetString() << "  "<<demo.GetChar(10) << std::endl;
    std::cout << demo.GetStringLens() << "  " << demo.GetArryLens() << std::endl;
    demo.MyAddEnd(‘y‘);
    std::cout <<  demo.GetString() << std::endl;
    demo.MyAddEnd("aaaaa");
    std::cout << demo.GetString() << std::endl;
    demo.MyAddEnd(123456);
    std::cout << demo.GetString() << std::endl;
    demo.MyAddEnd(123456.789);
    std::cout << demo.GetArryLens() << std::endl;
    std::cout << demo.PopupHead() << demo.PopupEnd() << std::endl;
    std::cout << demo.PopupHead() << demo.PopupEnd() << std::endl;
    std::cout << demo.PopupHead() << demo.PopupEnd() << std::endl;
    std::cout << demo.PopupHead() << demo.PopupEnd() << std::endl;
    std::cout << demo.MyCharReplace(‘o‘,‘@‘) << "   "<< demo.GetString() << std::endl;

      return 0;
}