Memory leak without allocating any memory? - c++

Question

I'm working on a coding assignment for a C++ class. When I run my program I seem to be dealing with a memory leakage issue, which is weird since I am NOT explicitly allocating any memory in my code. I ran the program under gdb, and it seems as though the program crashes when running the destructor for a Deck object. I tried stepping through the code, but I when I do so I end up in a host of .h files related to vectors. Then suddenly, it stops. I tried going to a TA for some help, but they seem to be as perplexed as I am on the issue.
# include <stdlib.h>
# include <time.h>
# include <iostream>
# include <vector>
# include <stdio.h>
using namespace std;
//function signatures
float bustProbability (const int);
class Deck
{
public:
//data members
vector <int> cardArray;
vector <int> wasteCards;
//constructor
Deck();
//methods
void shuffleDeck();
void populateDeckWithCards();
void removeCopyCards();
int dealCard();
int remainingCards();
void showCards();
};
void Deck::removeCopyCards() {
for (unsigned int i = 0; i < wasteCards.size(); i++) {
bool removedCopy = false;
for (unsigned int j = 0; j < cardArray.size() && removedCopy == false; j++) {
if (cardArray[j] == wasteCards[i]) {
cardArray.erase (cardArray.begin() + j - 1);
removedCopy = true;
}
}
}
}
int Deck::dealCard() {
if (remainingCards() > 0) {
int tmp = cardArray.back();
wasteCards.push_back(tmp);
cardArray.pop_back();
return tmp;
}
else {
populateDeckWithCards();
removeCopyCards();
shuffleDeck();
//shuffle method
int tmp = cardArray.back();
cardArray.pop_back();
return tmp;
}
}
void Deck::populateDeckWithCards() {
//populate regular cards into array
for (int i = 2; i <= 10; i++) {
for (int j = 0; j < 4; j++) {
cardArray.push_back(i);
}
}
//populate J, Q, K into array
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 4; j++) {
cardArray.push_back(10);
}
}
//populating array with Aces... treating them as special case '100'
for (int i = 0; i < 4; i++) {
cardArray.push_back(100);
}
return;
}
void Deck::showCards() {
for (unsigned int i = 0; i < cardArray.size(); i++) {
cout << cardArray[i] << endl;
}
}
Deck::Deck() {
wasteCards.clear();
cardArray.clear();
populateDeckWithCards();
shuffleDeck();
}
void Deck::shuffleDeck() {
int n = cardArray.size();
for(int a = n-1; a > 0; a--) {
int min = 0;
int max = a;
int j = min + rand() / (RAND_MAX / (max-min + 1) + 1);
int tmp = cardArray[a];
cardArray[a] = cardArray[j];
cardArray[j] = tmp;
}
return;
}
int Deck::remainingCards() {
return cardArray.size();
}
class Player {
public:
//data members
vector <int> playerHand;
//constructor
Player();
//methods
bool isBust();
int count();
void hit(Deck&);
void stand();
bool muckHand();
void showHand();
};
Player::Player() {
playerHand.clear();
}
void Player::showHand() {
for (unsigned int i = 0; i < playerHand.size(); i++) {
cout << playerHand[i] << endl;
}
return;
}
int Player::count() {
int handCount = 0;
for (unsigned int i = 0; i < playerHand.size(); i++) {
if (playerHand[i] != 100)
handCount += playerHand[i];
else {
if (playerHand[i] == 100) {
if ((handCount) > 11) {
handCount += 1;
}
else
handCount += 10;
}
}
}
return handCount;
}
bool Player::isBust() {
if (count() > 21)
return true;
else
return false;
}
void Player::hit(Deck& d) {
playerHand.push_back(d.dealCard());
}
void Player::stand() {
return;
}
bool Player::muckHand() {
playerHand.clear();
return true;
}
float bustProbability (const int threshHold) {
int threshHoldReached = 0;
Deck myDeck;
Player myPlayer;
Player dealer;
for (int i = 0; i < 10000; i++) {
myPlayer.hit(myDeck);
dealer.hit(myDeck);
myPlayer.hit(myDeck);
dealer.hit(myDeck);
while (myPlayer.count() < threshHold) {
myPlayer.hit(myDeck);
}
if (!(myPlayer.isBust())) {
++threshHoldReached;
}
myDeck.wasteCards.clear();
myPlayer.muckHand();
dealer.muckHand();
}
float bustFraction = float(threshHoldReached)/float(10000);
return bustFraction;
}
int main () {
cout << "blackjack simulation" << endl;
srand((unsigned int)time(NULL));
cout << bustProbability(19);
return 0;
}
I'm incredibly sorry for just posting my code, but I've spend 4 days on this issue, and I can't even begin to figure out what the problem is.

Answer 1

There is at least the line
cardArray.erase (cardArray.begin() + j - 1);
which seems to be dubious in case of j = 0