This document covers pointers in C programming. It discusses pointer basics like declaring and dereferencing pointers, pointer arithmetic, pointers to pointers, and complex pointer declarations. It also covers pointer operations, cautions around pointers, and reasons for using pointers like passing information to and from functions. Examples are provided for declaring and assigning pointers to variables and arrays.

1. Week 5

2. There are 10 types of people, those who understand
binary and those who don't

3. Pointers

4. why?
<data type> *ptr = <address>

5. Pointers and addresses
• The addressable units in memory is bytes
• A pointer contains the address of one byte of
memory
• pointers are usually 4 bytes

6. Notes
• Pointers are represented internally as unsigned
int on most systems
• %p
• arr [n] ====> *(arr + n)

7. Referencing and dereferencing
referencing :
&<variable name>
dereferencing:
*<pointer name>

8. Pointers and arrays
• Pointers and arrays are tightly coupled
• An array name is actually the address of the first
element of the array
• *(arr + i) is what is really happening

9. Pointer operations
• Assignment
• referencing and dereferencing
• Adding, subtracting an int , increment and
decrement
• &ptr
• (ptr1 - ptr2)
• Comparisons

10. Pointer arithmetic

12. • Pointer is just another variable
• They are stored in memory , so they have an
address as well
Pointers to pointers

13. How to read complex declarations ?

14. Complicated declarations
• int *arr [ ] ;
• float rain [5] [12];
• const double *p;
• double * const p;
• const double * const p;

15. Pointer cautions
• Exceeding the array boundary
• Dereferencing an uninitialized pointer

16. why pointers
• To Communicate info to and from functions
• As a return type of functions
• Needed with Embedded systems

17. int n = 5;
double x;
int *p1 = &n;
double*p2 = &x;
x = n;
p2 = p1;

18. int n = 5;
double x;
int *p1 = &n;
double *p2 = &x;
x = n;
p2 = p1;

19. int n = 5;
double x;
int *p1 = &n;
double *p2 = &x;
x = n;
p2 = p1;

20. int n = 5;
double x;
int *p1 = &n;
double *p2 = &x;
x = n;
p2 = p1;

21. int n = 5;
double x;
int *p1 = &n;
double *p2 = &x;
x = n;
p2 = p1;

22. Recursion

23. Expressions

24. Examples
• Sum
• Factorial
• Fibonacci

25. IRC

26. Interview !!!
• what does "const" mean
• compilation process
• Infinite loops
• set and clear a bit

27. Interview !!
const int a; int const a;
const int *a;
int * const a;
int const * a const;

28. Interview !
• The word "register"
• what is "Macros"
• #IF

33. See You Soon

34. Thanks