Deleting a temporal Array in C++ - c++

Question

I was working with dynamic memory from a book that I got. As far as I understand every time that we create a new variable we need to delete it, and set the pointer to null, so we don't have dangling pointers .
I created a program that stores values from users in a dynamic Array of [5], and whenever the user adds more I "expand" the array. When expanding, I use a temporary new array that gives me a tough time when I try to delete it. Why does this happen?
size_t arraySize(5), index(0);
int inputvalue(0);
int *ptemporal(nullptr);
int *pvalues = new int[arraySize];
for (;;){
cout << "Enter value or 0 to end: ";
cin >> inputvalue; //enter value
// exit loop if 0
if (!inputvalue) //if 0 break
break;
pvalues[index++] = inputvalue; //store values on pivalores
if (index == arraySize){ //if limit reached create space
cout << "Limit reached. Creating space...";
arraySize += 5; //5 new memory blocks
ptemporal = new int[arraySize]; //temporal value holder.
for (size_t i = 0; i < arraySize - 5; i++) //xfer values to temporal
ptemporal[i] = pvalues[i];
delete[] pvalues; // delete values to
pvalues = ptemporal; // assigning the same addres to pvalues.
**delete[] ptemporal; //causes a problem if I use the delete. if i comment the program works just fine.**
ptemporal = nullptr;
}
}
return 0;
}
**The two asterics are just to show were the problem occurs.

Answer 1

Your issue is that you are deleting ptemporal right after you copy the pointer to pvalues:
pvalues = ptemporal; // assigning the same addres to pvalues.
delete[] ptemporal; //causes a problem if I use the delete. if i commentt the program works just fine.**
In other words, you delete the memory you just created! So the next time you expand the vector, you try to delete it again, resulting in a double free error. This sort of error is where a debugger helps, so you can watch the variable values as your program executes.
// start
ptemporal = nullptr;
pvalues = /* location A */;
// first expansion
ptemporal = /* location B */;
// copy values from location A to B
delete[] pvales; /* location A */
pvalues = ptemporal; /* location B! */
delete[] ptemporal; /* location B */
ptemporal = nullptr;
// second expansion
ptemporal = /* location C */;
// copy values from location B to C, should segfault
// then you delete pvalues (aka location B) again!
// this results in a double free error
delete[] pvales; /* location B */
To fix this, simply remove the line delete[] ptemporal;

Answer 2

You dont need to delete pTemporal. You've deleted pValues and wish to hand over pTemporal into it.
delete [] pValues;
pValues = pTemporal;
pTemporal = NULL;