If I delete an app that has all my music and redownload it will it still be there?

I have an app on the iPhone that allows you to download music. That app and two others suddenly stopped working last night, and all three needed an update but wouldn't update or open. I deleted the other two and redownloaded them but they're diferent because they don't have music saved to them like this app. The other two apps were just kik and vine. So if I delete the app and redownload it will all of my music still be there or will I have to start from scratch?

Music will still be there doesn't matter if you delete or not its saved to your phone memory will always be in your music folder unless you reset phone or delete the song urself