help with fly

if(*(DWORD*)(pPlayerClient + 0x5F4) != NULL)
				{
					if(GetAsyncKeyState(VK_RSHIFT) &1)
						*(float*)(pPlayerClient + 0x5F4) = -2.125f;
					if(GetAsyncKeyState(VK_LSHIFT) &1)
						*(float*)(pPlayerClient + 0x5F4) = 1.0f;
				}