I'll tell you how to get the strReverse() done. Since this is a home assignment I'll only tell you how you could do it.

First of all you need to decide whether you want to do it the string or char...

Public is missing a colon, and get() method should look like this:
long get () const { return x; }

Why do you need set method to be const anyway?

You can do this by passing a pointer to char or a string.

#include <string>
void yourFunction(const char * filename); //we don't want to modify so it's const
void yourFunction(string filename);

You might want to try something like this, but yes it uses more CPU and memory.

#define YOUR_ARRAY_SIZE 256
#include <string.h>

char * getName(){
char buf[YOUR_ARRAY_SIZE];
...