Declaring a pointer

The pointer in c language can be declared using * (asterisk symbol). It is also known as indirection pointer used to dereference a pointer.

int *a; //pointer to int  
char *c;//pointer to char  

Pointer Example:

An example of using pointers to print the address and value is given below.

Pointer to array

int arr[10];  
int *p[10]=&arr; 

Pointer to a function

void show (int);  
void(*p)(int) = &display; 

 Pointer to Structure

struct st {  

   int i;  

    float f;  

}ref;  

struct st *p = &ref;  

Advantages of Pointer

• Pointer reduces the code and improves the performance.
• It is used to retrieving strings, trees, etc., and used with arrays, structures, and functions.
• We can return multiple values from a function using the pointer.
• It makes you able to access any memory location in the computer’s memory.

Usage of pointer

There are many applications of pointers in c language.

Dynamic memory allocation

• In C language, we can dynamically allocate memory using malloc() and calloc() functions where the pointer is used.

Arrays, Functions, and Structures

• Pointers in c language are widely used in arrays, functions, and structures.
• It reduces the code and improves the performance.

]]> https://www.wikitechy.com/interview-questions/c/what-is-pointer-in-c/feed/ 0 https://www.wikitechy.com/interview-questions/cpp/what-is-pointers-in-cpp/ https://www.wikitechy.com/interview-questions/cpp/what-is-pointers-in-cpp/#respond Fri, 19 Aug 2022 09:41:33 +0000 https://www.wikitechy.com/interview-questions/?p=4798

Syntax

datatype *var_name; 
int *ptr;

Sample Code

#include <iostream>
using namespace std;
int main() {
	int  x = 27;  
	int  *ip;        
	ip = &x;       
	cout << "Value of x is : ";
	cout << x << endl;
	cout << "Value of ip is : ";
	cout << ip<< endl;
	cout << "Value of *ip is : ";
	cout << *ip << endl;
	return 0;
}

Output

main () 
  {
  char *p1="Name"; 
  char *p2; 
  p2=(char *)malloc(20); 
  while(*p2++=*p1++); 
  printf("%s\n",p2); 
  } 

Answer : NULL