There are many ways to cook a hot dog. The key thing to remember is hot dogs are already cooked, so in essence, you are merely heating the hot dog to make it more palatable.
Here are the standard ways.
Boiling. Boil some water, throw the hot dog in. I usually cook it for 2 or 3 minutes, You can cook longer if you want.
Steam- Get a pot of water boiling, then put on a steamer over the water, drop the dog dog in and wait for it to heat through,
Grilling. You can grill hot dogs on the grill or on a griddle top, or in a sauce pan. Throw them on the heat and let them cook, be certain to turn occasionally to get them evenly heated.
Baking - Put the hot dog in the oven at whatever temperature you like to get them heated through. 350 is reasonable.
Broil - Put the hot dog on a baking sheet, set the broiled to broil, put the sheet under the heat and watch carefully. You will probably want to turn them half way to get them to cook evenly.
Deep Fry- Immerse the hot dog in hot oil.
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Uncooked (Right out of the Package) True the dogs are already cooked, but to be safe, heating them will kill any bacteria that might have latched onto them.