#include 
     
      #include 
      
       using namespace std;class MyString {public:	MyString();	MyString(const char* cstr);	MyString(const MyString &other);	MyString& operator=(const MyString &other);	size_t length() {		return size;	}	friend istream& operator>>(istream &in, const MyString &str);	friend ostream& operator<<(ostream &out, const MyString &str);	~MyString();protected:	char *data;	size_t size;};MyString::MyString() {	size = 0;	data = new char[1];	*data = '\0';}MyString::MyString(const char *cstr) {	if (cstr != NULL) {		size = strlen(cstr);		data = new char[size + 1];		strcpy(data, cstr);	} else {		size = 0;		data = new char[size + 1];		*data = '\0';	}}MyString::MyString(const MyString &other) {	if (!other.data) {		data = new char[other.size + 1];		*data = '\0';		size = 0;	} else {		size = other.size;		data = new char[1];		strcpy(data, other.data);	}}MyString& MyString::operator =(const MyString &other) {	/*if (this != &other) {		size = strlen(other.data);		char *temp = new char[size + 1];		strcpy(temp, other.data);		delete []data;		data = temp;	}	return *this;*/	if (this != &other) {		MyString strTmp(other);		char *pTmp = strTmp.data;		strTmp.data = data;		data = pTmp;	}
      
     

return *this;}MyString::~MyString() {	delete []data;}int main(){	char *s = NULL;	MyString str(s);	return 0;}