return parameter is not allowed?

[MisunKim]

I made CMyString class, and make operator=.
but in (operator=) function, there exists error.
================================================
class CMyString
{
private:
char *m_pStr; //dynamic array, changing the size
public:
CMyString();
CMyString(const CMyString &mystr);
CMyString(char str[]);
~CMyString();
CMyString& operator = (const CMyString &mystr);
};
CMyString::CMyString()
{
m_pStr = new char[1];
m_pStr[0] = NULL;

}
CMyString::CMyString(char str[])
{
int length=0;
length = strlen(str);
m_pStr = new char[length+1];
strcpy(m_pStr, str);
}
CMyString::CMyString(const CMyString &mystr)
{
int length=0;
length = strlen(mystr.m_pStr);
m_pStr = new char[length+1];
strcpy(m_pStr, mystr.m_pStr);
}
CMyString::~CMyString()
{
if(m_pStr!=NULL) {
delete [] m_pStr;
}
}
CMyString& CMyString::operator = (const CMyString &mystr)
{
return mystr;
}
==================================================
C:\Program Files\Microsoft Visual Studio\MyProjects\LearningPointer\1_pointer.cpp(70 ) : error C2440: 'return' : cannot convert from 'const class CMyString' to 'class CMyString &'
Conversion loses qualifiers

. ======================================
what is the problem? Is it related to constructor or destructor?
Can't I return parameter?
I greatly need your kind comment.

[JosAH]

CMyString& CMyString::operator = (const CMyString &mystr)
{
return mystr;
}
==================================================
C:\Program Files\Microsoft Visual Studio\MyProjects\LearningPointer\1_pointer.cpp(70 ) : error C2440: 'return' : cannot convert from 'const class CMyString' to 'class CMyString &'
Conversion loses qualifiers

. ======================================
what is the problem? Is it related to constructor or destructor?
Can't I return parameter?
I greatly need your kind comment.

Your parameter is a const and you attempt to return a non-const reference;
you can't 'cast away the const'. You either make the return type a const as
well or leave out the const for the parameter.

kind regards,

Jos

[newb16]

C:\Program Files\Microsoft Visual Studio\MyProjects\LearningPointer\1_pointer.cpp(70 ) : error C2440: 'return' : cannot convert from 'const class CMyString' to 'class CMyString &'
Conversion loses qualifiers

You cant return const object where return type is not const, because you cant' assign const object to non-const. You need to copy data from members of argument to member of this and return this.