I don't fully understand why Harry didn't die in Deathly Hallows?

EDIT:Harry Potter was one of the horcruxes, and that horcrux protected him from fully dying because he had a fragment of Vold's soul added to his own- he was half dead and half alive- which explains the choice of life or death for him- yet the horcrux in him was destroyed, which means that Harry didn't have to die to defeat Voldemort. In the end the force of Voldemort's defeat was just merely a blast of power than knocked Harry Potter down- since he was not a safe distance from Voldemort. WHen Nagini died Voldemort had no horcruxes left, just himself