My iPhone 4s camera stopped working?

Yesterday my camera was working completely fine, but out of nowhere it just stopped working? Now whenever I open my camera the screen is just black? Also, if I wanna take a pic on Instagram, it's the same deal with that. What should I do to fix it? Help ASAP!

Close any running apps by double tapping home button and then press and hold one of the icons till the red minus sign comes up.

After that press and hold the lock/power button and the home button until the device turns off and the apple comes back(do not leave plugged into computer while doing this)

If this does not work then restore on itunes or reset to factory.

if all else fails call 1800MYIPHONE

worked great to restore iphone camera… Thanks

it worked! Thanks so much!

Thank you! Camera issues are gone