Thread: A problem with vectors

Im not sure if I should be posting this here or the game programming forum.

Anyway...the deal is... I am using vectors instead of arrays to track PLAYER potions.

here is the code...I commented where the problems lie...there is over 400 lines of code so I am only going to post snippets.


Top of Town.cpp where I declared the vector and its iterator.

Code:

#include "Library.h"
#include "Globals.h"

using std::cin;
using std::cout;
using std::endl;

// I am not too sure of where to declare this vector
std::vector<POTION>potions(15);
std::vector<POTION>::iterator i;

void Armory(PLAYER*);
void ItemShop(PLAYER*);

ItemShop function

Code:

void ItemShop(PLAYER* player)
{
     cout << "As you step inside, a pleasant smell wafts up to your nose.  You see\n"
          << "a kindly heavyset older woman watering plants, that decorate the shop.\n" << endl;
     Pause();
     cout << "What would you like to do?\n"
          << "<1> Talk to the woman.\n"
          << "<2> Exit\n"
          << ">";
     int answer = -1;
     cin  >> answer;
     cin.clear();
     cin.ignore(INT_MAX,'\n');
     
     if (answer == 1)
     {
         cout << "Hello Traveler!  Welcome to Suzies Pots and Herbs.\n"
              << "How may I help you?\n" << endl;
         Pause();
         Clr_Scrn();
         
         bool shoploop = true;

         while (shoploop = true)
         {
         cout << "What do you want to do?\n"
              << "<1> Buy Potions\n"
              << "<2> Buy Spells\n"
              << "<3> View Stats\n"
              << "<4> Exit\n"
              << ">";
         int choice = -1;
         cin  >> choice;
         cin.clear();
         cin.ignore(INT_MAX,'\n');
         
         switch(choice)
         {
              case 1:
                   {
                       POTION* potionlist = new POTION[7];
                       potionlist[0].CreatePotion("Small Health Potion", 10, 30, 50);
                       potionlist[1].CreatePotion("Medium Health Potion", 30, 100, 100);
                       potionlist[2].CreatePotion("Large Health Potion", 100, 300, 1000);
                       potionlist[3].CreatePotion("Elixer", 9999, 9999, 10000);
                       potionlist[4].CreatePotion("Small Mana Potion", 10, 50, 100);
                       potionlist[5].CreatePotion("Medium Mana Potion", 30, 100, 100);
                       potionlist[6].CreatePotion("Large Mana Potion", 100, 300, 1000);
                       
                       cout << "Name: " << "Restore: " << "Price: " << endl;
                       for (int loop = 0; loop < 6; loop++)
                       {
                           cout << loop + 1 << potionlist[loop].GetName() << " " << 
                           potionlist[loop].GetMinRestore() << "-" << potionlist[loop].GetMaxRestore()
                           << potionlist[loop].GetPrice() << endl;
                           }
                       cout << "0: Exit\n"
                            << "What do you want to buy?\n";
                       int decision = -1;
                       cin  >> decision;
                       cin.clear();
                       cin.ignore(INT_MAX,'\n');
                       
                       if (decision > 0 && decision < 8)
                       {
                             if (player->GetGold() >= potionlist[decision-1].GetPrice())
                             {
                                  player->SpendGold(potionlist[decision-1].GetPrice());
                                  
                                  // places potion in vector
                                  potions.push_back(potionlist[decision-1]);
                                  
                                  // this is only to test to see the capacity of the vector
                                  // for some reason it outputs 30--when should be 15
                                  cout << endl << potions.capacity() << endl;
                                  
                                  // to test how much memory is inialized inside the vector
                                  // which for some reason outputs 16--when should be 1
                                  cout << potions.size() << endl << endl;
                                  
                                  // put this in just to see what the heck was going on and am now
                                  // more confused than ever!!!!
                                  // first 15 outputs is dobldegook
                                  // the 16th is the potion that you actually bought!!!
                                  for(i = potions.begin(); i != potions.end(); ++i)
                                  {
                                        cout << i->GetName() << endl;
                                        }
                                  
                                  cout << "You have purchased a " << potionlist[decision-1].GetName()
                                  << endl;
                                  cout << "Do you want to make another purchase? 1 for yes 2 for no\n";
                                  cin  >> shoploop;
                                  cin.clear();
                                  cin.ignore(INT_MAX,'\n');
                                  Clr_Scrn();
                                  delete [] potionlist;
                                  break;
                                  }
                             else
                             {
                                  cout << "You cant afford this!!\n" << endl;
                                  Pause();
                                  Clr_Scrn();
                                  delete [] potionlist;
                                  shoploop = true;
                                  break;
                                  }
                                  }
                       else if (decision == 0)
                       {
                            delete [] potionlist;
                            shoploop = false;
                            break;
                            }
                       else
                       cout << "Invalid Selection" << endl;
                       shoploop = true;
                       Pause();
                       Clr_Scrn();
                       break;
                       }

> potionlist[6].CreatePotion("Large Mana Potion", 100, 300, 1000);
Well this is off the end of your allocated memory, so fix that first.

>// I am not too sure of where to declare this vector
>std::vector<POTION>potions(15);
push_back creates a new element, so you don't need to create 15 elements here, unless you use something like:

Code:

potions[count] = potionlist[decision-1];

to store the new potion. Instead you can just use:

Code:

std::vector<POTION> potions;

As far as where to declare it, if you made a class you could declare it in the class. Otherwise in main(), and you'd pass this vector to any function which needed it.

Code:

// I am not too sure of where to declare this vector
std::vector<POTION>potions(15);

Declare the vector where it makes sense. Perhaps you could create a WORLD* structure or something and pass it to your functions along with the PLAYER*.

Code:

cin.ignore(INT_MAX,'\n');

Perhaps this would be a better idea:

Code:

cin.ignore(std::numeric_limits<std::streamsize>::max(),'\n');

I can't remember if it's streamsize, streambuf, or one of those with an underscore in it.

Well, the std::streamsize code is better because that's the actual data type that is used. INT_MAX is usually what std::numeric_limits<std::streamsize>::max() is set to, but not always. See here for a better description: http://cboard.cprogramming.com/showthread.php?t=82416

Oh yes, and apparently (I had forgotten this) streamsize is in <ios>:

Code:

#include <ios>      // For streamsize

http://cboard.cprogramming.com/showthread.php?t=85987

But even using INT_MAX is great. Most people just use 9999 or something.

Code:

while (shoploop = true)

Typo?