Why wont my iPhone 4s turn on?

Today when i woke up i saw the charger was on 33% when i dragged it out of the charger i went to school, while i was walking i took my phone out of my pocket and it was turned off, i tried to turn it on again but it just got to apple logo and then turned off again. I tried even reboot the iphone some few times but it still turned off.

So when i went home to charge it, it wouldn't charge, i did even let it charge for 4 hours, nothing happend, i tried to reboot it while it was charging it still nothing happend