Index

Chapter 11: Zombie Loss 😞

Now that we've coded what happens when your zombie wins, let's figure out what happens when it loses.
In our game, when zombies lose, they don't level down — they simply add a loss to their lossCount, and their cooldown is triggered so they have to wait a day before attacking again.
To implement this logic, we'll need an else statement.
else statements are written just like in JavaScript and many other languages:

if (zombieCoins[msg.sender] > 100000000) {
// You rich!!!
} else {
// We require more ZombieCoins...
}

Put it to the test

1. Add an else statement. If our zombie loses:
a. Increment myZombie's lossCount.
b. Increment enemyZombie's winCount.
c. Run the _triggerCooldown function on myZombie. This way the zombie can only attack once per day. (Remember, _triggerCooldown is already run inside feedAndMultiply. So the zombie's cooldown will be triggered whether he wins or loses.)

pragma solidity ^0.4.25;

import "./zombiehelper.sol";

contract ZombieAttack is ZombieHelper {
  uint randNonce = 0;
  uint attackVictoryProbability = 70;

  function randMod(uint _modulus) internal returns(uint) {
    randNonce++;
    return uint(keccak256(abi.encodePacked(now, msg.sender, randNonce))) % _modulus;
  }

  function attack(uint _zombieId, uint _targetId) external ownerOf(_zombieId) {
    Zombie storage myZombie = zombies[_zombieId];
    Zombie storage enemyZombie = zombies[_targetId];
    uint rand = randMod(100);
    if (rand <= attackVictoryProbability) {
      myZombie.winCount++;
      myZombie.level++;
      enemyZombie.lossCount++;
      feedAndMultiply(_zombieId, enemyZombie.dna, "zombie");
    } else {
      myZombie.lossCount++;
      enemyZombie.winCount++;
      _triggerCooldown(myZombie);
    }
  }
}