Electronic device and electronic system

An electronic system, comprising:

• an electronic device
• a rod having a first portion and a second portion opposite to each other, wherein the first portion comprises a touch head;
• a first communication module disposed inside the rod;
• a first sleeve slidably sleeved on the first portion of the rod and movable between a first position and a second position of the first portion, wherein when the first sleeve is at the first position, the first sleeve covers the touch head and is rotatable relative to the rod, and when the first sleeve is at the second position, the touch head is enabled;
• a second sleeve sleeved on the second portion of the rod, wherein the second sleeve is rotatable relative to the rod;
• and
• a processing unit disposed inside the rod and adapted to receive information of the first sleeve or the second sleeve rotating relative to the rod, wherein
• when the first sleeve is at the first position, the electronic device is adapted to serve as a roller-type input device, a function of the roller-type input device being controlled according to the information of the first sleeve or the second sleeve rotating relative to the rod;
• and
• when the first sleeve moves toward the second sleeve to the second position, the touch head is exposed from the first sleeve, and the touch head is enabled, so that the electronic device is adapted to serve as a stylus;
• and
• a body having an accommodating slot and comprising a second communication module in a signal connection to the first communication module, and the electronic device is detachably disposed in the accommodating slot.