Do I need to free the ptr? If so, how?
#include <iostream>
using namespace std;
void printFromPtr(int *ptr);
int main()
{
int a = 3;
int numPrint = 10000;
for (int i = 0; i < numPrint; i++)
{
printFromPtr(&a);
}
}
void printFromPtr(int* ptr)
{
cout << *ptr << endl;
}
The function is receiving a pointer from the caller, and does not know how the memory being pointed at was allocated, so it has no business trying to free it. Only the caller knows how it was allocated, so only the caller knows how to free it.
In this example, the caller is passing a pointer to a local variable a that is not allocated dynamically, so there is nothing to free manually. The variable will be gone when it goes out of scope.
There is no need to free any pointer as you are not doing any dynamic memory allocation here.
when we are doing dynamic memory allocation then we need to free pointers.
in your code you are passing pointer to local variable, so no need to free pointers.it will automatically remove(after reaching in out of scope.)
You should use delete only for pointers obtained by new. Beware of dangling pointers and of memory leaks. Be very afraid of undefined behavior. And in C++ you should prefer smart pointers, see this (and use standard containers when convenient). And you generally don't use malloc and free in C++ (only in C). However many implementations of new are internally using malloc, etc...
Read also about the rule of five, and about RAII, about pointer aliasing, about virtual address space, about constructors and destructors, about virtual method tables. See this question.
No.You have not allocated dynamic memory & no need to free the ptr.In your code ptr stores address of variable reside in the stack not the heap.
