Why won't my iPhone charge up? Is it my cell phone or the charger?

Ever since last nite my charger hasn't been working ( iPhone ) and the battery is stun so it's either the charger or the iPhone, which one is it?

Added (1). I meant the battery is low not stun

Buy a new charger and see if it the charger or the phone

Well, try a different charger… And then if it works its your charger. If it doesn't, it's your phone.

Try to use other charger, if it doesn't work, replace your battery… If the problem still exist it might be your phone connection.