How to delete an updating app?

I started updating an app but one of them updated normally and the other just says waiting and I have been updating other things normally but this one is messed up. Oh and up top right next to my battery percentage (I have an iPhone) it has that loading sign for internet but it hasn't updated or got anywhere and it has been 4 days… Is there a way to stop it or delete it?

If using the X next to the download doesn't do it, try holding down the home button so that the apps start jiggling with an X in the corner of each. Hit that X next to the app in question.
If that doesn't work, reboot (hold the main power button to shut down and after it shuts down, restart it.) that should do the trick.