pwn.college

Objective

Extract fields value, damage, ItemType type, and last from items.json and save in the Item struct.

Prerequisites

This project requires that the MUD program from project 5 is working and passing the tests related to movement and viewing the player's inventory.

Upgraded to C++, alter Makefile, and verify it compiles

The Mud Shop functionality of this level will be written in C++
Your program from level 5 has been converted to a C++ program (we just renamed all the .C files to .cpp)
Use cdhw to change to your work area (if accessing via remote terminal).
create a shop.h and shop.cpp
In the Makefile

Change all the .c extensions to .cpp
Add shop.o to OBJS
Change the main.bin target's compiler from CC to CXX, which will use the g++ compiler instead of gcc
To the bottom of the dependencies list, add shop.o: shop.h

Run make to verify the conversion was successful.

If it did not compile because of an undefined reference to your functions, try executing make clean && make. This is because the project is converted from C to C++.
If it did not compile because of a malloc statement causing an invalid conversion from void *, this is caused by a slight difference between C and C++. C++ is requiring that malloc specifically cast the result to match the pointer.
To fix, use casting to change the return type to match the variable being allocated.


      // Add a cast to the malloc changing 
      Room *rooms = malloc(sizeof(Room)*(roomMaxId+1));
      // to the following, which now has a (Room*) just after equals sign
      Room *rooms = (Room*) malloc(sizeof(Room)*(roomMaxId+1));

It should now be compiling.

Create an enum in data.h

Add the following enum to data.h


    typedef enum ItemType {
        ITEM_TYPE_NONE=-1,
        ITEM_TYPE_GENERAL,
        ITEM_TYPE_QUEST,
        ITEM_TYPE_POTION,
        ITEM_TYPE_WEAPON,
        ITEM_TYPE_ARMOR    
    } ItemType;

Upgrade Item struct in data.h

The Item struct needs some new fields


      int value;      // the value of the item
      int damage;     // damage the item does when used as a weapon
      ItemType type;  // the type of item, general, quest, potion, weapon, armor 
      bool last;      // marks the last item in the items list

Update load_json_items in data.cpp to load the new fields

value and damage will use extract_int
type will need a new function that equates general, quest, potion, weapon, armor to their enum counterparts.
last is used to identify the last record in the array, so it will be false for all records except the last with an id > -1
One approach for setting last would be to track a lastValidItemId
If you are not a student in the class, then don't use last here, use a hardcoded macro variable with the value 1600 called MAX_JSON
- Each time the code finds an Id, then set the lastValidItemId
- After the loop, set the last value for the item at the index of lastValidItemId to true

Update main() in main.cpp to print out the new fields

Update the printf for the items
Add the new data for value, damage, type, last
This should result in item 1697 looking like this:
```
1697 Crimson Sword 104097 320 3 1
```

Get the flag by running tester and passing all the tests.