Rubiks C++ code

#include<iostream>

using namespace std;
// filling the faces of cube
void fill (char *a, char b) {
	for (int i = 0; i<3; i++){
		for (int j = 0; j<3; j++){
			a[i][j] = b;
		}
	}
}
// performing moves on a cube
// by interchanging the pieces
void interchange (char &a, char &b, char &c, char &d) {
	char e, f, g;
	e = b;
	f = c;
	g = d;
	b = a;
	c = e;
	d = f;
	a = g;
}
int main () {
//6 faces of rubik's cube
	char f[3][3];
	char b[3][3];
	char r[3][3];
	char l[3][3];
	char u[3][3];
	char d[3][3];
//filling the faces
	fill(f, 'W');
	fill(b, 'Y');
	fill(r, 'O');
	fill(l, 'R');
	fill(u, 'G');
	fill(d, 'B');
	/* Testing of interchange function*/
	char x, y, z, p;
	cin >> x >> y >> z >> p;
	interchange(x,y,z,p);
	cout << x << " " << y << " " << z << " " << p << " " << endl;
}