1. Pointer Arithmetic
By Anand George

2. Pointer types Classification based on the type of data it points
Types of pointers
Pointer to Data
Pointers to functions ( code )
All pointers are of same size 32 bit in a 32 bit OS respective of what type it is.

3. Pointers to data Different types int * char * float* ACustomStructure*
All 32 bit size..
Then what is the difference?

4. Difference is..
The number of locations the pointer jumps when you add 1 ( or any number for that matter) to the pointer variable.
The pointer arithmetic is counter intuitive ( some time you get 1+1 = 2, some times 3, 4 like that ) and depends on the type of data.

5. What does that mean? Suppose int *ptr = 100;
Now the address inside variable ptr = 100;
now what is ptr + 1 in a 32 bit OS?
intuitive answer is 101 but actual answer is 104 ( assuming int is 4 byte )

6. What is the reason?
by the statement ptr+1 we are telling the compiler “hey compiler I'm already pointing to an integer (int *ptr ) and now I want to point to the NEXT INTEGER ( ptr+1 )” and NOT the next memory location.
Next integer is 4 bytes away so compiler has to add 4 instead of 1 to go to NEXT integer.

7. Demo #include <stdio.h> void main() { } int *ptrA = (int*)100;
int *ptrResult = ptrA + 1;
printf("ptrA = %d, ptrResult = %d ", ptrA, ptrResult ); }

8. Houses in a street

9. Jump is equal to sizeof ( data type)
char* jump is 1
int* jump is 4
sizeof operator
pointer arithmetic has only – and + no division, multiplication or any other operation.

10. Demo Allocating a chunk and accessing it with pointer arithmetic.
Using different types of pointer. char, int ,short
Using * to dereference the pointer variable.
sizeof operator

11. Summary Pointer types based on size of data it points to int* char*
Difference between the pointer types is the amount it jumps when arithmetic is done.
sizeof operator.

12. Thank You