C++ 重载=操作符

#include<stdio.h>#include<iostream>#inlcude<stdlib.h>class CString{public：    CString()    {        m_str=NULL;    }    CString operator =(const CString &n_str)    {        if(this== &n_str)        {            return *this;        }        if(m_str!=NULL)        {            if(m_str != n_str.m_str)            {                char *s = malloc(sozeof(n_str.m_str));                if(s==NULL)                {                    return *this;                }                strcpy(s,n_str.m_str);                delete m_str;                m_str = s;            }        }        return *this;    }private:    char *m_str;};