Why did Alexander[the great] quit?

Question:I heard one version:
It was customary for Alexander to ask his defeated king the question..."Now that I have won and brought you to your knees, how would you like me to deal with you?"
Porus on being asked said "Victory or loss can happen to anyone....I am a king and would like to be treated like one....as I would have, if I had won..
I presume Alexander having met a brave king ended his pursuit.

Best Answer - Chosen by Asker: I heard one version:
It was customary for Alexander to ask his defeated king the question..."Now that I have won and brought you to your knees, how would you like me to deal with you?"
Porus on being asked said "Victory or loss can happen to anyone....I am a king and would like to be treated like one....as I would have, if I had won..
I presume Alexander having met a brave king ended his pursuit.

FIRST ALEXANDER THE GREAT NEVER EVER QUIT OR SURRENDERED AND HERE IS THE STORY since you mentioned that you heared one version so there must be other version too to hear

King Porus fought the Battle of the Hydaspes River with Alexander in 326 BC. After fierce fighting and very heavy casualties on both sides, he was defeated by Alexander in a Pyrrhic victory.[3] The battle is often considered to be Alexander's hardest fought battle,[4][5] so hard that it caused his army to mutiny against him afterwards.[6] In a famous meeting with Porus - who had suffered many arrow wounds in the battle and had lost his sons, who all chose death in battle rather than surrender -- Alexander reportedly asked him, "How would you like to be treated?" Porus replied, "As befits a king." Alexander was so impressed by the brave and powerful response of King Porus that he released him back to his Kingdom and gave him the captured land of a neighbouring Kingdom whose ruler had fled. [7]

Later, King Porus is reported to have participated in Alexander's conquests further east in India. During the attack and destruction of Sagala, Porus rallied Alexander and supplied elephants as well as 5,000 troops:

"At this point too, Porus arrived, bringing with him the rest of the elephants and some five thousand Indians" Arrian, Anabasis of Alexander, V.24.4
In recognition for his support, Alexander gave him the dominion over the territories he had conquered, as far as the Hyphasis:

"He added the territories as far as the river Hyphasis to Porus' dominion, and he himself began to return towards the Hydraotes." Arrian, Anabasis of Alexander, V.29.2

he always make friends on kings he defeated. i guess he did not really quit because he died at a young age

You didn't read far enough in that history book... Alexander died after becoming dispondent about the death of his gay lover.

because his forces refused to move further

Alexandria is a great place to swim