class my_string woes

I can't figure out what's wrong with my + function. 'my_string temp' doesn't appear to be assigning a memory address to temp.s or the correct value to temp.len and so the terminates with an error. Please help.

Code:

#include <iostream>
#include <string.h>
using namespace std;

class my_string {
	char *s;
	int len;
public:
	my_string(int n) { s = new char[n+1]; len = n; }
	my_string() { len = 255; s = new char[255]; }
	~my_string() { delete s; }
	void assign(char* st) { strcpy(s, st); len = strlen(st); }
	int length() { return (len); }
	void print() { cout << s << "\nLength: " << len << "\n"; }
	friend my_string operator +(my_string& a, my_string& b);
};

main()
{
	char achar[] = "Yay!", bchar[] = " Coolio!";

	my_string a, b, c;

	a.assign(achar), b.assign(bchar);

	c = a+b;
}

my_string operator +(my_string& a, my_string& b)
{
	my_string temp;

	temp.assign(strcpy(temp.s, a.s));
	if (a.len + b.len < 255)
		temp.assign(strcat(temp.s, b.s));
	else
		cerr << "Max length exceeded in concatenation.\n";
	return (temp);
}

void print(char *c)
{
	cout << c << "\nLength is " << strlen(c) << "\n";
}

Problem resolved. Resolution: inadequate specification of constructors.