This presentation tells about the basic fundamentals of pointers in C programming language

1. Fundamentals of pointers
UNIT IV
By : Shivanshu Verma

2. Introduction to Pointers
A pointer is a variable that holds a memory address. This address is the location of
another object(typically another variable) in a memory.

3. Pointers notations in C
 You can use a pointer on the right-hand side of an assignment statement to
assign its value to another pointer. When both Pointers are the same type, the
situation is straightforward.

4. Declaration of pointer
 A pointer is declared as “data-type*pointer-variable-name”.
 * symbol specifies it is a pointer variable. You must prefix * before variable name
to declare it as a pointer.
 Pointer-variable-name is a valid C identifier i.e. the name of pointer variable.

5. Operations that can be performed on a computer
 Assignment
 Value finding
 Taking a pointer address
 Adding an integer to a pointer
 Incrementing a pointer
 Subtracting an integer from a pointer
 Decrementing a pointer
 Differencing
 comparision

6. Use of pointers in programming exercises
 Pointers are more efficient in handling arrays and structures
 Pointers are used to return multiple values from a function
 Pointer allow dynamic memory allocation and deallocation in C.
 Pointers allow to refer and pass a function as a parameter to functions

7. Parameters passing in pointers
 These are of two types
 Call by value
 Call by reference

8. Call by value
 In call by value method, the value of actual parameters is copied into the formal
parameters in other words we can say that the value of variable is used in the
function call in the call by value method.
 The actual parameters is the argument which is used in the function call whereas
formal parameter is the argument which is used in the function definition.

9. Call by reference
 In call by reference, the address of the variable is passed into the function call as
the actual parameters.
 The value of the actual parameters can be modified by changing the formal
parameter since the address of the actual parameter is passed.

10. Array and character using pointers

11. Dynamic Allocation
 It can be done by four methods
1. Malloc
2. Calloc
3. Realloc
4. free

12. Malloc
 It stores data in a one memory chunk
 It does not initializes memory at 0
 When memory is insufficient it points at NULL value
 Syntax: <pointer_name>=(cast type *)malloc(size)

13. Calloc
 It creates multiple block of memory
 It points at NULL value if memory is insufficient
 It initializes memory at 0
 Suntax : <pointer_name>=(cast_type *)calloc(n,size)

14. Realloc
 It is used to increase or decrease the size of memory. Basically used after malloc or
calloc
 Syntax: <pointer_name>=realloc(ptr_name,new size)

15. Free
Put it at the place(usually end of program) to remove the memory of at pointer
Syntax: free(pointer_name)

16. Thank You