Harry Potter triumphs over voldemort after coming back from the dead. if you dont believe me read the 7th book.
Voldemort dies, Harry does not.
I'm not sure I understand the question but Voldemort does not win and Harry Potter kills him.
No, Harry Potter wins.
the final battle between harry and voldemort where harry kills voldemort
Surprise: yes, he did.
When Voldemort used the Elder Wand (of which Harry is actually the true master) to cast the spell "Avada Kedavra" and Harry cast "Expelliarmus", Voldemort's curse rebounded killing Voldemort. And the Battle Of Hogwarts was won...
Harry was accidentally made into Voldemort's Horcrux. This created a connection between Harry's and Voldemort's mind. This caused nightmares which Harry was able to check by using Occlumency.
Dumbledore battles Voldemort for a long time. Keep firing spells and eventually you will win.
I'm assuming you're talking about the battle at the Ministry at the end of the Order of the Phoenix. Voldemort takes over Harry's body and talks through Harry. Voldemort can't stay in Harry's body/mind, though, because of Harry's utter goodness. The love and friendship that Harry feels for his friends is actually painful for Voldemort to experience firsthand, so Harry is able to force Voldemort out of his head.
Between Harry and Voldemort, it is difficult to determine who is greater in terms of strength alone. Voldemort was one of the greatest magician in the magical world - so powerful that people feared to take his name. On the other hand, he was cruel and without any emotions. He knew nothing of love and sacrifice. Harry, though not as skilled in magic as Voldemort was a good wizard. He was one of the best Quidditch players and very powerful in magic. In the final battle, it was actually luck and his ownership of the Elder wand that let Harry win, actually.
Harry wins the battle of the Deathly Hallows in the fight between him and Voldemort, and Voldemort is defeated.
Harry does, of course. You didn't actually think that J.K. Rowling was going to let Voldemort win did you?