#pragma once
#include "mylib.h"

namespace mylib {
	class String {
	public:
		//構(gòu)造函數(shù)集合
		String(void);
		String(const char* cha);
		String(const String& str);
    
		//運(yùn)算符重載集合
		const char* operator= (const char* cha);
		const String& operator= (const String& str);
		bool operator== (const char* cha) const;
		bool operator== (const String& str) const;
		char& operator[] (const size_t index) ;
		operator std::string(void) { return std::string(_ch); }
        //內(nèi)置方法集合
		const size_t lenght(void) const;
		const char *c_str(void) const;
	private:
		//私有函數(shù)
		void str_init(const size_t lg, const char *cha);  
		//私有數(shù)據(jù)
		char*          _ch;     //字符串頭指針
		size_t         _lenght;  //字符串長(zhǎng)度
	};

	//字符串類的流操作符重載
	std::ostream& operator<< (std::ostream &os,String &obj) 
	{
		for(size_t i = 0; i <= obj.lenght(); ++i)
			os << obj[i];
		return os;
	}
	std::istream& operator>> (std::istream& is,String& obj ) 
	{
		for(size_t i = 0; i < obj.lenght();++i)
			is >> obj[i];
		return is;
	}
	//私有函數(shù)集合
	void String::str_init(const size_t lg, const char *cha) 
	{
		if(!cha)
		{
			_lenght = 0; 
			_ch = 0;
		}
		else
		{
			_lenght = lg;
			_ch = new char [_lenght + 1];
			strcpy(_ch,cha);
		}
	}

	//公有函數(shù)集合 
	//構(gòu)造函數(shù)集合
	String::String(){ str_init( 0,0 ); }
	String::String(const char *cha) 
	{ 
		str_init(strlen(cha),cha);
	}
	String::
		String(const String& str)
	{
		str_init(str._lenght,str._ch);
	}

	//方法集合
	const size_t String::lenght() const { return _lenght;}
	const char* String :: c_str() const    { return _ch;}

	//操作符集合
	char& String::operator[] (const size_t index) 
	{
		assert(index >= 0 && index <= _lenght);
		return _ch[index];
	}
    
	bool String::operator== (const String& str) const
	{
		if(str._ch)
           return false;
        if(_lenght != str._lenght)
           return false;
        if( strcmp(_ch,str._ch) )
           return false;
		
		return true;
	}
	bool String::operator== (const char *cha) const
	{
		if(cha)
			return false;
		if( _lenght != strlen(cha) )
			return false;
		if( strcmp(_ch,cha) )
			return false;

		return true;
	}

	const String& String::operator= (const String& str) 
	{
		if(!str._ch)
		{
			_lenght = 0;
			delete [] _ch;
			_ch=0;
		}
		else 
		{
			_lenght = str._lenght;
			delete [] _ch;
			_ch = new char[_lenght + 1];
			strcpy( _ch,str._ch );
		}

		return *this;
	}
	const char* String::operator= (const char *cha)
	{
		if( !cha ) 
	    {
           _lenght = 0;
           delete [] _ch;
           _ch = 0;
        }
        else
	    {
            _lenght = strlen( cha );
            delete [] _ch;
            _ch = new char[_lenght + 1];
            strcpy(_ch,cha);
         }
        return this->_ch;
	} 
};