Write a C program demonstrating examples on pointers

A pointer is a variable that stores the address of another variable.

Features of Pointers

• Pointer saves the memory space.

• The execution time of a pointer is faster because of direct access to memory location.

• With the help of pointers, the memory is accessed efficiently, i.e., memory is allocated and deallocated dynamically.

• Pointers are used with data structures.

Declaring a pointer

int *p;

It means ‘p’ is a pointer variable that holds the address of another integer variable.

Initialization of a pointer

Address operator (&) is used to initialize a pointer variable.

For example,

int qty = 175;
int *p;
p= &qty;

Accessing a variable through its pointer

To access the value of the variable, the indirection operator (*) is used.

Program

 Live Demo

#include<stdio.h>
void main(){
   //Declaring variables and pointer//
   int a=2;
   int *p;
   //Declaring relation between variable and pointer//
   p=&a;
   //Printing required example statements//
   printf("Size of the integer is %d
",sizeof (int));//4//
   printf("Address of %d is %d
",a,p);//Address value//
   printf("Value of %d is %d
",a,*p);//2//
   printf("Value of next address location of %d is %d
",a,*(p+1));//Garbage value from (p+1) address//
   printf("Address of next address location of %d is %d
",a,(p+1));//Address value +4//
   //Typecasting the pointer//
   //Initializing and declaring character data type//
   //a=2 = 00000000 00000000 00000000 00000010//
   char *p0;
   p0=(char*)p;
   //Printing required statements//
   printf("Size of the character is %d
",sizeof(char));//1//
   printf("Address of %d is %d
",a,p0);//Address Value(p)//
   printf("Value of %d is %d
",a,*p0);//First byte of value a - 2//
   printf("Value of next address location of %d is %d
",a,*(p0+1));//Second byte of value a - 0//
   printf("Address of next address location of %d is %d
",a,(p0+1));//Address value(p)+1//
}

Output

Size of the integer is 4
Address of 2 is 6422028
Value of 2 is 2
Value of next address location of 2 is 10818512
Address of next address location of 2 is 6422032
Size of the character is 1
Address of 2 is 6422028
Value of 2 is 2
Value of next address location of 2 is 0
Address of next address location of 2 is 6422029