Of course this is a common question and a easy problem to tackle...

Take your puppy out right after he's eaten. He will probably do both. Take him to the same place each time so he associates that place with doing his business. If you catch starting to pee inside, yell him "NO!" and take him outside right away. Don't scold him or he may become confused, but always praise him when he goes outside.

See I told you, simple!