Pointers in C Language

Pointer in C 

Pointer  

Pointers constitute a fundamental element of the C programming language. They serve the purpose of storing the memory addresses of various entities, including variables, functions, and even other pointers. The utilization of pointers facilitates low-level memory access, dynamic memory allocation, and a range of additional functionalities within C.A pointer variable points to a data type (like int) of the same type, and is created with the * operator.

syntax:-    type *name

Declaration:-    int *aoi;   

 //int is a type of pointer   

//*aoi is a pointer variable.

program to print the address of variable using unary operator.

#include<stdio.h>

#include<conio.h>

#include<string.h>

main()

{

int i,j;

float f;

char p[20];

clrscr();

i=50;

j=60;

printf("\n The value of i is= %d",i);

printf("\n The address of i is= %u",&i);

printf("\n The value of j is= %d",j);

printf("\n The address of j is= %u",&j);

getch();

}

//name pointer:- value of variable through address.

#include<stdio.h>

#include<conio.h>

#include<string.h>

main()

{

int i,j;

float f;

char name[20];

clrscr();

i=50;

j=60;

printf("\n The value i is= %d",i);

printf("\n The value i through address is= %d",*(&i));

printf("\n The address i is= %u",&i);

printf("\n The value j is= %d",j);

printf("\n The value j through address is= %d",*(&j));

printf("\n The address j is= %u",&j);

printf("\n The value float is= %f",dec);

printf("\n The value float through address is= %f",*(&dec));

printf("\n The address float dec is= %u",&dec);

printf("\n The value char name is= %s",name);

printf("\n The value of name through address is= %s",*(&name));

printf("\n The address char name is= %u",&name);

getch();

}

//program to create a pointer variable using your name and use it.

#include<stdio.h>

#include<conio.h>

main()

{

int i, *pankaj; //*pankaj store the address.

clrscr();

i=50;

pankaj=&i;

printf("\n The value of i is %d",&i);

printf("\n The value of i through addres is%d",*pankaj);

printf("\n The address of i is %u",pankaj);

*pankaj=*pankaj+20;

printf("\n the original value is %d",i);

printf("\n the updated value is %d"*pankaj);

getch();

}

//    pankaj shows the address of variable.

//    *pankaj shows the value of variable.

//    *pankaj+20 shows the updated value of variable.

//program to use pointer as an Array .

#include<stdio.h>

#include<conio.h>

#include<string.h>

main()

{

int i,n, *roll;

//you can use *roll variable as pointer variable to store addrss.

// OR use it as array of undefinite element.

// here we use *roll as array not pointer.

clrscr();

printf("\n How many records you want to enter");

scanf("%d",&n);

for(i=0;i<n;i++)

{

printf("\n Enter the roll number= ");

scanf("%d",&roll[i]);

}

for(i=0;i<n;i++)

{

printf("\n The roll number is %d",roll[i]);

}

getch();

}

Note:- 

"&" (uniary operator)        //returns only one operand

m=&count;        //m has the address of count.

q=*m;        //q has the value of count.     //q recieves the value at address m.