C++ Suppose a String class has the following definition and a main which uses it: a) Write a one argument constructor for the String class, with a char * as the argument, This function first allocates 80 characters from the heap using new and points str to it, then copies the argument to that memory, and assigns len the length of the string. (5 points) b) Write a destructor for String that cleans up the allocated memory. (5 points) c) Write the operator assignment to assign one String into another (5 points).