this stack has a memory leak. Find the cause and apply fix

 this stack has a memory leak. Find the cause and apply fix:

using System;

class MtStack{

private Object[] elements;

private int size = 0;

public MyStack(int initialCapacity){

elements = new Object[initialCapacity];

}

public void Push(object o){

EnsureCapacity();

elements[size++] = o;

}

public object Pop(){

if(size == 0){

throw new InvalidOperationException();

}

return elements[--size];

}

private void EnsureCapacity(){

if(elements.Length == size){

Object[] old = elements;

elements = new Object[2*size + 1];

old.CopyTo(elements,0);

}

}

}

=====================

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🔍 Problem: Memory Leak in Pop()

In your class:

public object Pop(){
    if(size == 0){
        throw new InvalidOperationException();
    }
    return elements[--size];  // ❗ Leak: object reference remains in elements[size]
}

The popped object is no longer logically in the stack, but its reference still exists in the internal elements[] array. This prevents the garbage collector from freeing it, especially for large or complex objects.

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✅ Fix: Clear the Reference After Pop

You need to null out the reference after decrementing size:

object obj = elements[--size];
elements[size] = null; // ✅ Clear reference to avoid memory leak
return obj;

---

✅ Corrected Full Code

using System;

class MyStack
{
    private Object[] elements;
    private int size = 0;

    public MyStack(int initialCapacity)
    {
        elements = new Object[initialCapacity];
    }

    public void Push(object o)
    {
        EnsureCapacity();
        elements[size++] = o;
    }

    public object Pop()
    {
        if (size == 0)
        {
            throw new InvalidOperationException("Stack is empty");
        }

        object obj = elements[--size];
        elements[size] = null; // ✅ Clear reference
        return obj;
    }

    private void EnsureCapacity()
    {
        if (elements.Length == size)
        {
            Object[] old = elements;
            elements = new Object[2 * size + 1];
            old.CopyTo(elements, 0);
        }
    }
}

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🧪 Test Example

public static void Main()
{
    MyStack stack = new MyStack(2);
    stack.Push(new object());
    stack.Push(new object());
    stack.Pop(); // now the reference is cleared
}

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✅ Summary

Issue	Fix
Reference held after Pop()	elements[size] = null;
Prevents GC from reclaiming memory	✅ Fix clears unused object references