C++ Error...IDK what is wrong!

[Frederick Lenz]

// assignment operator

#include <iostream>
using namespace std;

int main ()
{
int a,b,c,d,e;
a=2;
a = b;
b = c;
c = d;
d = e;

cout << "If A=2, E=D, D=C, C=B, and B=A then E=" << e << endl;

return 0;
}