Index

Chapter 10: Zombie Victory 😄

Now that we have a winCount and lossCount, we can update them depending on which zombie wins the fight.
In chapter 6 we calculated a random number from 0 to 100. Now let's use that number to determine who wins the fight, and update our stats accordingly.

Put it to the test

1. Create an if statement that checks if rand is less than or equal to attackVictoryProbability.

2. If this condition is true, our zombie wins! So:
a. Increment myZombie's winCount.
b. Increment myZombie's level. (Level up!!!!!!!)
c. Increment enemyZombie's lossCount. (Loser!!!!!! 😫 😫 😫)
d. Run the feedAndMultiply function. Check zombiefeeding.sol to see the syntax for calling it. For the 3rd argument (_species), pass the string "zombie". (It doesn't actually do anything at the moment, but later we could add extra functionality for spawning zombie-based zombies if we wanted to).

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);
    // Start here
    if (rand <= attackVictoryProbability) {
      myZombie.winCount++;
      myZombie.level++;
      enemyZombie.lossCount++;
      feedAndMultiply(_zombieId, enemyZombie.dna, "zombie");

    }
  }
}