cout << " diff Difference method" << endl;
cout << " diff2 Optimized difference method (default)" << endl;
cout << " idiff2 Optimized difference method with integer math" << endl;
cout << " diff Difference method" << endl;
cout << " diff2 Optimized difference method (default)" << endl;
cout << " idiff2 Optimized difference method with integer math" << endl;