segmentation fault(core dumped) on Ubuntu - c++

Question

I have read few topics about same problem, but i can't find what's wrong in my code. This is header file:
#pragma once
class Queue
{
private:
float *elements;
int count;
float newElement;
public:
Queue();
Queue(int);
Queue(Queue &);
~Queue();
void enqueue(float);
float dequeue();
int getCount();
};
And .cpp file:
#include "Queue.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
Queue::Queue()
{}
Queue::Queue(int arrSize)
{
this->count = arrSize;
float *elements = new float[arrSize];
for(int i = 0; i < arrSize - 1; i++)
{
newElement = rand()% 4000;
newElement /= 100;
elements[i] = newElement;
}
}
void Queue::enqueue(float element)
{
size_t newSize = count + 1;
float *new_elements = new float[newSize];
memcpy(new_elements, elements, newSize);
count = newSize;
delete [] elements;
elements = new_elements;
elements[count] = element;
}
float Queue::dequeue()
{
float firstElement = elements[0];
size_t newSize = count - 1;
float *new_elements = new float[newSize];
memcpy(new_elements, elements, newSize);
count = newSize;
delete [] elements;
elements = new_elements;
return firstElement;
}
int Queue::getCount()
{
return count;
}
Queue::~Queue()
{
delete [] elements;
}
int main(int argc, char *argv[])
{
srand(time(NULL));
Queue queue(4);
queue.enqueue(3);
}
I was trying to figure out where my mistake is, but I'm begginer in C++.
I think that something is wrong i my "dequeue" method, by after trying to fix it, it's still the same.

Answer 1

There are several problems
The default constructor doesn't initialize its members
Queue::Queue(int arrSize) has a local variable elements, which shadows the member elements. The consequence, this constructor doesn't initialize its member
enqueue should copy count * sizeof(float) bytes, not newSize bytes
as #Vladimir noticed, enqueue assigns one element beyond the allocated memory. Should be elements[count - 1] = element;
dequeue should copy newSize * sizeof(float) bytes, not newSize bytes