VC++ threads deadlocked - multithreading

Question

The following program goes into a deadlock. Can anyone please tell me why?
#include<cstdlib>
#include<windows.h>
#include<iostream>
using namespace std;
class CircularQueue
{
public:
CircularQueue(int s)
{
size = s;
array = (int*)malloc(sizeof(int) * size);
head = tail = -1;
InitializeCriticalSection(&critical_section);
}
CircularQueue(void)
{
size = default_size;
array = (int*)malloc(sizeof(int) * size);
head = tail = -1;
InitializeCriticalSection(&critical_section);
}
void initialize(int s)
{
EnterCriticalSection(&critical_section);
size = s;
array = (int*)realloc(array, sizeof(int) * size);
head = tail = -1;
LeaveCriticalSection(&critical_section);
}
void enqueue(int n)
{
EnterCriticalSection(&critical_section);
tail = (tail + 1) % size;
array[tail] = n;
LeaveCriticalSection(&critical_section);
}
int dequeue(void)
{
EnterCriticalSection(&critical_section);
head = (head + 1) % size;
return array[head];
LeaveCriticalSection(&critical_section);
}
private:
int *array;
int size;
int head, tail;
CRITICAL_SECTION critical_section;
bool initialized;
static const int default_size = 10;
};
DWORD WINAPI thread1(LPVOID param)
{
CircularQueue* cqueue = (CircularQueue*)param;
cqueue->enqueue(2);
cout << cqueue->dequeue() << endl;
return 0;
}
DWORD WINAPI thread2(LPVOID param)
{
CircularQueue* cqueue = (CircularQueue*)param;
cqueue->enqueue(3);
cout << cqueue->dequeue() << endl;
return 0;
}
int main(void)
{
HANDLE thread1_handle;
HANDLE thread2_handle;
CircularQueue cqueue;
HANDLE array[2];
thread1_handle = CreateThread(NULL, 0, thread1, &cqueue, 0, NULL);
thread2_handle = CreateThread(NULL, 0, thread2, &cqueue, 0, NULL);
array[0] = thread1_handle;
array[1] = thread2_handle;
WaitForMultipleObjects(1, array, TRUE, INFINITE);
CloseHandle(thread1_handle);
CloseHandle(thread2_handle);
printf("end\n");
return 0;
}

Answer 1

In dequeue(), you have a return statement before the LeaveCriticalSection() call. If you had compiler warnings turned up higher, it would probably have told you about this!