The war started because the Romans wanted Sicily's granaries, and they felt threatened by the Carthaginians. Rome copied the model of a Carthaginian ship, and added a corvus. The Romans won peace from Carthage and the Carthaginians left Sicily.
The war started because Hannibal attacked Rome from Spain from the Southern Gaul, and brought elephants to break through their lines. The Roman won the 2nd Punic War by attacking Carthage while Hannibal was in Italy. The Romans won a huge sum of money, all of Carthage's territories, and Spanish resources.
The war started when the Romans attacked Carthage when they started showing signs of regaining power. Rome won the war by burning the Carthaginians fields, and salting them. They also killed the Carthaginians, or sold them into slavery. Rome became the leading power of the Mediterranean world.