Overview
In Clash of Clans, the Cannon is the first defensive structure that players can build. It deals relatively high damage per second to a single targets and can only hit ground units.
Damage Type: Single Target
Attack Speed: 1 attack per 0.8 sec
Range: 9 units
Target: Ground units only
Building Size: 3x3
-from clashofclans wikia
-Cannons have a high rate of fire and a decent range, which makes them an ideal deterrent for Wall Breakers; have extremely low health
-Cannons are very useful for keeping Giants from attacking other defenses
-Defend Mortars and Wizard Towers by placing them within range of Cannons
-Make sure Cannons are placed within range Air Defenses, because Cannons are unable to target air units, or at least in range of an Archer Tower or Wizard Tower
-Upgrade these structures and Mortars first at lower levels, as they are one of your main ground defenses. They are also the cheapest and most common defensive structure available, which makes them a good initial investment
Offensive Strategy
-from clashofclans wikia
-Cannons are on of the few defensive units that can not attack air units. This makes them easy pickings for Balloons, Dragons or Minions if they are not within range of Air Defenses, Archer Towers or Wizard Towers
-Cannons are only able to damage one unit at a time. This makes it very easy to overwhelm them with large groups of Archers or Barbarians