What is Pointer ?
A pointer is a special variable whose value is the address of another variable. In simple word, Pointer is also kind of a variable that is used to store address of variables or a memory location.
How to initialize a Pointer ?
Defining Pointer is a step-by-step procedure, like this ->Step 1: Defining a Pointer Variable
We need to define a Pointer variable first by specifying the data type and variable name.Syntax :
data_type *pointer_var;
Example :
int *p;
//Here int is the data type of the pointer variable and ‘p’ is the name of that variable.
//The ‘*’ (asterisk) sign is used to declare the pointer.
Step 2: Assigning the Value
After declaring we need to assign the address of a variable to the pointer variable.Syntax :
pointer_var = &main_var;
Example :
p = &var;
//Here ‘p’ is the pointer variable and ‘var’ is the name of that variable whose address is being stored.
//The ‘&’ (asterisk) sign is used to assign the address to a pointer.
A sample program of usage of Pointer Variable :
#include<stdio.h>
int main() {
int Eruditors = 47;
int *p;
p = &Eruditors;
//Instead of declaring & assigning separately we can declare & assign a pointer only once. For example,
//int *p = &Eruditors;
printf("Value of Eruditors Variable : %d\n",Eruditors);
//Value assigned in int Eruditors variable
printf("Value of *p Variable : %d\n",*p);
//Value of *p variable that indicates to the value of Eruditors variable
printf("Address stored in p Variable : %p\n",p);
// Accessing the address using pointer variable
printf("Address of Eruditors Variable : %p\n",&Eruditors);
//Accessing the address without using pointer variable
return 0;
}
Output :

Key Points about Pointer :
- ~ At the time of initializing, we can assign the 'NULL' value in a pointer variable. It assigns '0'. For example, int *p = NULL;
- ~ '%p' format specifier is used for pointer variable.
- ~ Four arithmetic operators that can be used in pointers: ++, --, +, -
- ~ C allows us to have pointer on a pointer and so on.
Advantages of an Pointer in C :
- ~ It reduces the code and improves the performance.
- ~ We can get access of any memory location access by pointer.
- ~ A pointer can be used to Arrays and Functions also.
- ~ We can return multiple values from a function using the pointer.
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