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Annalyn's Infiltration
Annalyn's Infiltration

Annalyn's Infiltration

Learning Exercise

Introduction

Booleans

The bool type (short for boolean) has only two values -- true and false. The true and false literal values are case insensitive in code.

<?php

$value_is_true = true;
$value_is_false = false;

Boolean values are often use in logical expressions as the result of an operator and then used in control structures.

Logical Operators

There are several logical operators:

  • !$a: returns true if $a is not true
  • $a && $b: returns true if $a and $b are both true
  • $a || $b: returns true if either $a or $b are true
Caution

There is an and and or operator and they are complementary to && and || respectively. They do not have the same behaviour as && and || and may produce unexpected results, and as such their use is discouraged.

Instructions

In this exercise, you'll be implementing the quest logic for a new RPG game a friend is developing. The game's main character is Annalyn, a brave girl with a fierce and loyal pet dog. Unfortunately, disaster strikes, as her best friend was kidnapped while searching for berries in the forest. Annalyn will try to find and free her best friend, optionally taking her dog with her on this quest.

After some time spent following her best friend's trail, she finds the camp in which her best friend is imprisoned. It turns out there are two kidnappers: a mighty knight and a cunning archer.

Having found the kidnappers, Annalyn considers which of the following actions she can engage in:

  • Fast attack: a fast attack can be made if the knight is sleeping, as it takes time for him to get his armor on, so he will be vulnerable.
  • Spy: the group can be spied upon if at least one of them is awake. Otherwise, spying is a waste of time.
  • Signal prisoner: the prisoner can be signalled using bird sounds if the prisoner is awake and the archer is sleeping, as archers are trained in bird signaling so they could intercept the message.
  • Liberate prisoner: Annalyn can try sneaking into the camp to free the prisoner. This is a risky thing to do and can only succeed in one of two ways:
    • If Annalyn has her pet dog with her she can rescue the prisoner if the archer is asleep. The knight is scared of the dog and the archer will not have time to get ready before Annalyn and the prisoner can escape.
    • If Annalyn does not have her dog then she and the prisoner must be very sneaky! Annalyn can free the prisoner if the prisoner is awake and the knight and archer are both sleeping, but if the prisoner is sleeping they can't be rescued: the prisoner would be startled by Annalyn's sudden appearance and wake up the knight and archer.

You have four tasks: to implement the logic for determining if the above actions are available based on the state of the three characters found in the forest and whether Annalyn's pet dog is present or not.

1. Check if the 'Fast Attack' action is possible

Implement a function named canFastAttack that takes a boolean value which indicates if the knight is awake. This function returns true if the 'Fast Attack' action is available based on the state of the character. Otherwise, returns false:

<?php
$is_knight_awake = true;

$infiltration = new AnnalynsInfiltration()
$infiltration->canFastAttack($is_knight_awake);
// => false

2. Check if the 'Spy' action is possible

Implement a function named canSpy that takes three boolean values, indicating if the knight, archer and the prisoner, respectively, are awake. The function returns true if the 'Spy' action is available based on the state of the characters. Otherwise, returns false:

<?php
$is_knight_awake = false;
$is_archer_awake = true;
$is_prisoner_awake = false;

$infiltration = new AnnalynsInfiltration()
$infiltration->canSpy($is_knight_awake, $is_archer_awake, $is_prisoner_awake);
// => true

3. Check if the 'Signal Prisoner' action is possible

Implement a function named canSignal that takes two boolean values, indicating if the archer and the prisoner, respectively, are awake. The function returns true if the 'Signal Prisoner' action is available based on the state of the characters. Otherwise, returns false:

<?php
$is_archer_awake = false;
$is_prisoner_awake = true;

$infiltration = new AnnalynsInfiltration()
$infiltration->canSignal($is_archer_awake, $is_prisoner_awake);
// => true

4. Check if the 'Liberate Prisoner' action is possible

Implement a function named canLiberate that takes four boolean values. The first three parameters indicate if the knight, archer and the prisoner, respectively, are awake. The last parameter indicates if Annalyn's pet dog is present. The function returns true if the 'Liberate Prisoner' action is available based on the state of the characters and Annalyn's pet dog presence. Otherwise, it returns false:

<?php
$is_knight_awake = false;
$is_archer_awake = true;
$is_prisoner_awake = false;
$is_dog_present = false

$infiltration = new AnnalynsInfiltration()
$infiltration->canLiberate(
    $is_knight_awake,
    $is_archer_awake,
    $is_prisoner_awake,
    $is_dog_present
);
// => false
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