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[HavingPhun]

Code: [Select]

error: cannot dynamic_cast '((ProgramManager*)this)->ProgramManager::EMan.EntityManager::EntityContainer.std::map<_Key, _Tp, _Compare, _Alloc>::operator[]<int, Entity*, std::less<int>, std::allocator<std::pair<const int, Entity*> > >((*(const key_type*)(&((ProgramManager*)this)->ProgramManager::PlayerID)))' (of type 'std::map<int, Entity*>::mapped_type {aka class Entity*}') to type 'class Player*' (source type is not polymorphic)
Do I perhaps have to modify the classes themselves somehow?

[cerapa]

It doesn't know that Entity is polymorphic. Entity needs to have a virtual function.

[HavingPhun]

Well, that was strangely simple. All I had to do was make the destructor for "Entity" virtual. Thanks everyone.

[Moghjubar]

Been taking a small break from my big stuff and doing small things, funtimes.  Made an IRC bot using winsock today, got it working on twitch (and threaded and all that)... and now poking around the Twitter API.  Think I can make something that tweets the last timeline tweet of a specified account to an IRC channel.

[TheBiggerFish]

I finally managed to get Arch to install successfully. I also managed to connect to my school's wifi, which was easier said than done. Turns out that they not only use WPA2-Enterprise PEAP MSCHAPv2 (the earlier version, not the current) but also disable certificate authentication. No wonder that it took less time to connect writing my own network configs over using NetworkManager back when I ran Mint.

This sounds like a facepalm moment.
So, yeah.
*facepalm*

[Gatleos]

This GUI library requires that I use function object callbacks with the signature "void()", but I need to set the callback to a member function, which means I need to std::bind it to a raw pointer. The problem is that, seemingly at random, the pointer gets invalidated by something. So the function gets called, but the "this" argument is pointing at some garbage data and I end up getting a memory access error. I only ever create a single instance of the class in question, so I have no idea what could be causing its location in memory to shift around.

[TheBiggerFish]

I finally managed to get Arch to install successfully. I also managed to connect to my school's wifi, which was easier said than done. Turns out that they not only use WPA2-Enterprise PEAP MSCHAPv2 (the earlier version, not the current) but also disable certificate authentication. No wonder that it took less time to connect writing my own network configs over using NetworkManager back when I ran Mint.

This sounds like a facepalm moment.
So, yeah.
*facepalm*

Nah, more that this school does not know how to do a proper wireless network correctly.

Like I said, facepalm moment.  Or headdesk.

[Telgin]

This GUI library requires that I use function object callbacks with the signature "void()", but I need to set the callback to a member function, which means I need to std::bind it to a raw pointer. The problem is that, seemingly at random, the pointer gets invalidated by something. So the function gets called, but the "this" argument is pointing at some garbage data and I end up getting a memory access error. I only ever create a single instance of the class in question, so I have no idea what could be causing its location in memory to shift around.

My guess is that it's memory corruption elsewhere.  Are you on Linux?  I'd try Valgrind on it to see if it recognizes any invalid memory writes.  If you're on Windows I think Visual Studio may have something similar now, but maybe not in the free version.

[3man75]

Spoiler (click to show/hide)

#include <iostream>
#include <ctime>
#include <cstdlib>

using namespace std;

int main(){

   int userChoice, compChoice;

   srand(time(0)); //RNG here.

   cout << "Welcome to the game of games.\t" << endl
      << endl << endl;


   cout << "1. is for rock, 2 is for paper, and 3 is for scissors. Now pick a number.\t" << endl
      << endl << endl;

   cin >> userChoice;

   cout << endl << endl << endl << "You have picked " << userChoice << " .\t" << endl
      << endl << endl;

   if (userChoice == 1){
      cout << "Rock." << endl << endl
         << endl;
   }
   else if (userChoice == 2){

      cout << "Paper" << endl << endl

         << endl;
   }
   else if (userChoice == 3){

      cout << "Scissors" << endl << endl

         << endl;
   }

   while (userChoice >= 4 || userChoice < 0 || !cin){
      cout << "Have you no shame! You didn't pick 1-3. Try again." << endl
         << endl << endl;

      cin >> userChoice;

      //In case people decide to really break the program.

      cin.clear();
      cin.ignore(3);
   }
   compChoice = ((rand() % 3) + 1);

   cout << "Your opponent picked: " << compChoice << endl
      << endl << endl;

    if (userChoice == 1 && compChoice == 2){
       cout << "Your opponent picked: " << compChoice << endl
          << endl << endl;
   //user rock comp paper
   }

   else if (userChoice == 1 && compChoice == 3){
      cout << "Your opponent picked: " << compChoice << endl
         << endl << endl;

      cout << "You win!" << endl << endl << endl;
   // user rock comp scissors
   }
   else if (userChoice == 2 && compChoice == 1){
      cout << "Your opponent picked: " << compChoice << endl
         << endl << endl;
      cout << "You lose!" << endl << endl << endl;
   //user paper comp rock
   }
   else if (userChoice == 2 && compChoice == 3){
      cout << "Your opponent picked: " << compChoice << endl
         << endl << endl;
      cout << "You lose!" << endl << endl << endl;
   //user paper comp scissor
   }
   else if (userChoice == 3 && compChoice == 1{
      cout << "Your opponent picked: " << compChoice << endl
         << endl << endl;
      cout << "You lose!" << endl << endl << endl;
   //user scissors comp rock
   }
   else if (userChoice == 3 && compChoice == 2){
      cout << "Your opponent picked: " << compChoice << endl
         << endl << endl;
      cout << "You lose!" << endl << endl << endl;
   //user scissors comp paper
   }
   while (userChoice == compChoice){
      cout << "You have tied with your opponent. Try again. \t" << endl << endl << endl;

      cin >> userChoice;
      //When opponent picks same as player they do not get a tie breaker.
   }
   
   








   system("pause");

   return 0;

}

Making a rock,paper, scissors game and I can't find where my error is. Compilers talking about a missing semicolon but I can't find that anywhere.

[Moghjubar]

Should be able to find it in build message, but if not... try this:

Use /* */ and comment out the bottom half of your code.  If you still get the error, its in the top section probably.

[3man75]

Found it!

I was missing a ) statement on one of the ifs.

[Reelya]

This GUI library requires that I use function object callbacks with the signature "void()", but I need to set the callback to a member function, which means I need to std::bind it to a raw pointer. The problem is that, seemingly at random, the pointer gets invalidated by something. So the function gets called, but the "this" argument is pointing at some garbage data and I end up getting a memory access error. I only ever create a single instance of the class in question, so I have no idea what could be causing its location in memory to shift around.

c++ I'm guessing. Are you using the new keyword to create the object in the heap? if you do that and store the returned pointer from new, it should never be changed.

[Gatleos]

c++ I'm guessing. Are you using the new keyword to create the object in the heap? if you do that and store the returned pointer from new, it should never be changed.

Yep, and it's SFGUI, which has a policy that all objects in the library can only be created as shared_ptrs. All widgets have a Create function like this (see the first function), so those should all be allocated dynamically on the heap. My own class, which contains these widgets, is a singleton for testing purposes, and the only instance of it is created like this:

Code: [Select]

shared_ptr<DeployGroupMenu> DeployGroupMenu::instance() {
static auto dgm = make_shared<DeployGroupMenu>(DeployGroupMenu());
return dgm;
}
That class is the one that I keep losing a pointer to, and I still can't find a pattern in when it happens. It seemed to happen consistently whenever I changed the text in a certain label, which caused the window's hierarchy of widgets to resize itself. The weirdest part is that the input that caused this resize also caused other member function callbacks to occur, but only this specific callback seemed to have a garbage "this" pointer when it was executed. I guess I just have to test a few more things.

My guess is that it's memory corruption elsewhere.  Are you on Linux?  I'd try Valgrind on it to see if it recognizes any invalid memory writes.  If you're on Windows I think Visual Studio may have something similar now, but maybe not in the free version.

I do have access to a linux machine, so maybe I'll give valgrind a try.

[RoguelikeRazuka]

You won't believe guys but some say programming languages are simply a form of representation of algorithms, and in order to become a programmer I should focus on learning algorithms rather than on learning a programming language. Are they completely right? Whether they are or not, where do I start from? Which books (or another resources) on algorithms would you guys particularly suggest and which algorithms is it necessary to know for every programmer?

[3man75]

Spoiler (click to show/hide)

#include <iostream>
#include <ctime>
#include <cstdlib>

using namespace std;

int main(){

   int userChoice, compChoice;

   int rock = userChoice = 1;


   srand(time(0)); //RNG here.

   cout << "Welcome to the game of games.\t" << endl
      << endl << endl;


   cout << "1. is for rock, 2 is for paper, and 3 is for scissors. Now pick a number.\t" << endl
      << endl << endl;

   cin >> userChoice;

   cout << endl << endl << endl << "You have picked " << userChoice << " .\t" << endl
      << endl << endl;

   if (userChoice == 1){
      cout << "Rock." << endl << endl
         << endl;
   }
   else if (userChoice == 2){

      cout << "Paper" << endl << endl

         << endl;
   }
   else if (userChoice == 3){

      cout << "Scissors" << endl << endl

         << endl;
   }

   
   compChoice = ((rand() % 3) + 1);




   while (userChoice == compChoice){
      cout << "You have tied with your opponent. Try again. \t" << endl << endl << endl;

      cin >> userChoice;
      compChoice = ((rand() % 0) + 1);
      //When opponent pick the same as player.
   }

   while (userChoice >= 4 || userChoice < 0){
      cout << "Have you no shame! You didn't pick 1-3. Try again." << endl
         << endl << endl;

      cin >> userChoice;

      //In case people decide to use negatives or numbers higher  than 3.

   }


   //Below are the winning conditions.

   if (userChoice == 1 && compChoice == 2){
      cout << "Your opponent picked: " << compChoice << endl
         << endl << endl;
      cout << "You lose" << endl << endl << endl;
      //user rock comp paper
   }

   else if (userChoice == 1 && compChoice == 3){
      cout << "Your opponent picked: " << compChoice << endl
         << endl << endl;

      cout << "You win!" << endl << endl << endl;
      // user rock comp scissors 
   }
   else if (userChoice == 2 && compChoice == 1){
      cout << "Your opponent picked: " << compChoice << endl
         << endl << endl;
      cout << "You lose!" << endl << endl << endl;
      //user paper comp rock
   }
   else if (userChoice == 2 && compChoice == 3){
      cout << "Your opponent picked: " << compChoice << endl
         << endl << endl;
      cout << "You lose!" << endl << endl << endl;
      //user paper comp scissor
   }
   else if (userChoice == 3 && compChoice == 1){
      cout << "Your opponent picked: " << compChoice << endl
         << endl << endl;
      cout << "You lose!" << endl << endl << endl;
      //user scissors comp rock
   }
   else if (userChoice == 3 && compChoice == 2){
      cout << "Your opponent picked: " << compChoice << endl
         << endl << endl;
      cout << "You win!" << endl << endl << endl;
      //user scissors comp paper
   }
   


   system("pause");

   return 0;

}

Found a problem that after a tie it won't check for incorect responces (Because it's already been done). Something else happens when I swtich them around.

Another one is that if I switch the two loops around then something happens that after I've tied and then input wrong statements that my program will accept a wrong statement before it simply just dosen't declare a winner. This is C++ btw.