Pointer

Introduction to C Pointer

• A pointer in C is a derived data type.
• Memory management related task can be performed very easily using C pointers.
• Pointer variables can be used to access and manipulate values stored in the memory cells.
• Pointer variable contains memory addresses as their values. 
• Following two special operators are very useful while using pointers:
• * is known as value at operator.
• & is known as address of operator.

Declaration of Pointer Variable

int *p1;

• This will declare a pointer to an int. 
• * is used to indicate that p1 is pointer type variable.
• We can store memory addresses of int variable in this pointer variable (p1).
• We can declare pointer to any data type. For example
• float *p1;
• char *ch1;

Advantages of Pointers

• Pointer allows us to perform dynamic memory management.
• Pointer can be used to return multiple values from a function.
• Pointers are more efficient in handling arrays and string type of variables.
• Handle structures (records) efficiently.
• Pointers reduce the complexity of C programs.
• Possible to create data structure like linked lists, trees, graphs.

Sample Pointer Programs

• C program to print Memory Addresses of Variables.

• Use of pointer to access the Array elements.

• C program to demonstrate use of null pointer.
• Dynamic memory allocation
• Array of Pointers
• Finding length of string using pointer
• Accessing structure using pointer

Example of Pointer in C program

#include<stdio.h>
int main()
{
 int number;
 int *p1; //pointer variable declaration

 number=5;
 p1 = &number;

 printf("Value in number variable = %d \n", number);
 printf("Value in p1 variable = %d", p1);
 return 0;
}

Output of the program:

Value in number variable = 5
Value in p1 variable = 2293432

Note: You may get some different value for p1.