operator overloading + prototype

//operator overloading
dystring operator +(const char *str); //concatenate strings with string
constant. Example: str + "hello"
dystring operator +(dystring dystr); //concatenate two strings. Example:
str1 + str2
friend dystring operator +(const char *str, dystring dystr);
//concatenate string constant with string. Example: "hello" + str
operator ovrloading +(const char *str)

use: concatenate dystring with string constant and return the result in
the form of dystring object.
Example: str + "hello"