Program Gives An Error Every Time After Working Once - c++

Question

I'm attempting to implement my own array using pointers in C++. I'm using Visual Studio. I'm relatively new to C++, so if there is something obvious that I'm missing bear with me. But when I run it the first time, it works as intended. However, the next time I run it, I get one of two errors. One of the errors is
Unable To Start Program, Access Denied.
"the path of the file"
Access Is Denied
The other one that comes up rarely is
main.cpp has triggered a breakpoint
I think it has something to do with a wrong use of pointers, however that doesn't explain why it works the first time. Here is the code:
In main.cpp:
#include <iostream>
#include <vector>
#include "linked_list.hpp"
#include "trie.hpp"
#include "stack.hpp"
#include "queue.hpp"
#include "array.hpp"
int main() {
data_structures::array arr(5);
arr.set(4, 1);
int fourth_index = arr.get(4);
std::cout << fourth_index;
}
In array.hpp:
#pragma once
namespace data_structures {
class array {
private:
int* start;
public:
array(int size) {
start = new int(0);
for (int i = 1; i < size; i++) {
*(start + i) = 0;
}
}
public:
void set(int index, int val) {
if (index == 0) {
start = new int(val);
} else {
*(start + index) = val;
}
}
int get(int index) {
return *(start + index);
}
};
}
The first time, I get the correct output:
1
Then the next time I get the error I stated above.

Answer 1

Try changing this line:
start = new int(0);
to:
start = new int[size];
new int(0) is initializing "start" as a pointer to just one int with a value of 0. Instead, you need to allocate the memory necessary to hold your array. I suspect you're running into issues because you're writing into memory that you haven't allocated yet.
As a side note, make sure to add a destructor and free your memory.

Answer 2

Well you must be right! It is a memory issue and the error message "main.cpp has triggered a breakpoint" on windows indicates corruption of the heap in this case! I didn't have access to the hpp files you used apart from array.hpp
Let's start with some memory issues that your code is making
While initializing your array you are only initializing a single integer. But you need multiple integers in the array when you say want an array of size 5, you need to declare 5 integers. So you should declare an entire memory space for that. I am using malloc for this.
int* start = (int *)malloc(size*sizeof(int))
Secondly in your code for set there is a logical error that would change your start pointer from the original array which should not be happening. Instead you should just change the value at start.
*start = val;