设计并实现一个字符串类CString，该类至少具有以下方法：

给分

#include 
#include 
#include 
using namespace std;
class CString
{
public:
CString(const char*);
~CString();
int getLength();
CString& merge(const CString&);
string show() const;
private:
string* str;
};
CString::CString(const char* s):str(NULL)
{
str = new string(s);
if(NULL == str)
{
cerr<<"initial CString error!"<exit(0);
}
}
CString::~CString()
{
delete str;
}
int CString::getLength()
{
return str->length();
}
string CString::show() const
{
return *str;
}
CString& CString::merge(const CString& s)
{
(*str) += s.show();
return *this;
}
int main()
{
CString s1("Hi");
CString s2("You!");
s1.merge(s2);
cout<return 0;
}