1. Pointers And Memory
Acknowledgement: THE Slides are Prepared FROM SLIDES PROVIDED By NANCY M. AMATO AND Jory Denny

2. Pointers
Pointers are variables storing the memory address of another data/variable/object.
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3. Pointers
Pointers are variables storing the memory address of another data/variable/object.
int x=5;
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4. 5 x y Pointers and Memory 0x04
Pointers are variables storing the memory address of another data/variable/object.
int x=5;
int *y = &x;
Operator & gives the memory address of a variable/object
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5. 5 x y z Pointers and Memory 0x04 0x04
Pointers are variables storing the memory address of another data/variable/object.
int x=5;
int *y = &x;
Operator & gives the memory address of a variable/object
int* z = y;
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6. 5 x y z Pointers and Memory 0x04 0x04 int *y = &x; int* z = y;
What will happen if I write: *z = 0; ?
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7. x y z Pointers and Memory 0x04 0x04 int *y = &x; int* z = y;
What will happen if I write: *z = 0; ?
* is a dereferencing operator – gives the content of the memory address pointed by (or stored in) the pointer
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8. Memory allocation – new operator
new allocates space to hold the object.
new calls the object’s constructor.
new returns a pointer to that object.
Point * A = new Point (10, 20);

9. Memory Deallocation – Delete Operator
For every call to new, there must be exactly one call to delete.
Point * A = new Point (10, 20); //allocates memory …
delete A; //deallocates or frees the memory

10. Pointers And Array An array can act as a pointer
Array name is a pointer to first element in the array
Pointer can be indexed like an array
int arr[5] = {1,2,3,4,5};
cout << arr[2] << "," << *(arr+2); //displays 3,3

11. Dynamic Allocation & Deallocation of Array
Static allocation:
You must know the size of the array before hand
int arr[10];
Dynamic Allocation
Size of the array can be passed as a variable
size_t sz = 10;
int* arr = new int[sz];
Deallocate : delete[] arr;

12. Memory
HEAP
MEMORY
STACK

13. Stack vs. Heap Heap – Dynamic Allocation Point *p = new Point(5,10);
double *amount = new double[5];
Stack – static allocation
Point p(5,10);
double amount[5];
What happens when p goes out of scope?

14. Pair programming Driver – One at the keyboard
Navigator – Helps direct driver
Teamwork and communication are key here
Switch roles frequently!