Volume occupied by real gases
When you are "containing" a gas in a container then you are by definition restricting its volume. Lets assume you heat the gas. If the volume is confined then the pressure will increase. Similarly, two different gases will have different pressures if confined to the same volume. 

If you somehow control the pressure (there is a movable piston) then a real gas will occupy less volume because of its intermolecular interactions. 

Also see this: Volume of different gas in a container