This document discusses pointers in C programming. It defines pointers as a data type that contains the memory address of another variable. Pointers allow dynamically allocating memory and reduce program complexity. The document shows how to declare and initialize pointer variables, use pointers to access values, demonstrates pointers to pointers, and uses pointers with arrays. Examples are provided to illustrate pointers, pointer to pointer, and using pointers in arrays and 2D arrays.

1. Pointers
Created By:
Name: Abhimanyu Mehta
V.V.P Engineering College, Rajkot

2. Pointers

3. Introduction
• A Pointer is a derived data type in C.
• Pointers contains memory addresses as their
values.
• Pointer reduces the length and complexity of
the program.
• It allows working with dynamically allocated
memory.

4. • Definition:
Pointer variable: Pointer variable is a variable
that contains an address, which is a location of
another variable in memory.

5. Declaring pointer variables
• The declaration of the pointer variable takes
the following form:
data_type *pt_name;

6. Initialization of pointer variable
• The process of assigning the address of a
variable to a pointer variable is known as
initialization.
• Initialization:
int *p=#

7. Example
• W.a.p to illustrate the use of indirection operator ‘*’ to access the value pointed to
by a pointer.
#include<stdio.h>
void main()
{
int x,y;
int *ptr;
x=10;
ptr=&x;
y=*ptr;
clrscr();
printf(“n%d”,x);
printf(“n %d is stored at address %u”,x,&x);
printf(“n %d is stored at address %u”,*&x,&x);
printf(“n %d is stored at address %u”,*ptr,ptr);

8. printf(“n %u is stored at address %u”,ptr,&ptr);
printf(“n %d is stored at address %u”,y,&y);
*ptr=30;
printf(“n now x=%d”,x);
getch();
}
Output:
Value of x =10
10 is stored at address 65524
10 is stored at address 65524
10 is stored at address 65524
65524 is stored at address 65520
10 is stored at address 65522
Now x =30

9. Pointer to pointer
• A variable that is pointer to pointer must be
declared using additional indirection operator
symbols in front of the name.
int **p2;

10. Example
w.a.p to demonstrate the pointer to pointer.
#include<stdio.h>
void main()
{
char c=‘z’,*cp,**pcp;
float f=10.2;*fp,**pfp;
int i=987,*ip,**pip;
cp=&c;
pcp=&cp;
fp=&f;
pfp=&fp;
ip=&i;
pip=&ip;
clrscr();
printf(“n”);
printf(“n c=%c, cp=%u, pcp=%u”, c,&cp,&pcp);

11. printf(“n i=%d, ip=%u, pip=%u”, i,&ip,&pip);
printf(“n f=%f, fp=%u, pfp=%u”, f,&fp,&pfp);
getch();
}
Output:
c=z,cp=65522,pcp=65520
i=987,ip=65508,pip=65506
f=10.200000,fp=65514,pfp=65512

12. Pointers and Arrays
w.a.p to find out maximum number from 1-D array using pointer.
#include<stdio.h>
void main()
{
int a[5],i;
int *p,max=0;
clrscr();
p=a;
for(i=0;i<5;i++)
{
printf(“ a[%d]”,i);
scanf(“%d”,p);
p++;
}

13. {
max=*p;
}
p++;
}
printf(“n max=%d”,max);
getch();
}
Output:
Enter the value for a[0]= 12
Enter the value for a[1]= 23
Enter the value for a[2]= 3
Enter the value for a[3]= 40
Enter the value for a[4]= 51
Max=51

14. Arrays of pointers
• Arrays of pointers is a collection of pointers of
same data type.
• Syntax:
data type *name[size];

15. Example
Demonstrate the use of pointer in 2-D.
#include<stdio.h>
void main()
{
int m[2][2];
int i,j;
clrscr();
for(i=0;i<2;i++)
{
for(j=0;j<2;j++)
{
printf(“nEnter value for row = %d,column= %d:-”,i,j);

16. scanf(“%d”,m[i][j]);
}
}
for(i=0;i<2;i++)
{
for(j=0;j<2;j++)
{
printf(“m[%d][%d]=%d”,i,j,*(*(m+i)+j));
}
printf(“n”);
}
getch();
}

17. Output:
Enter the value for row=0, column=0:-1
Enter the value for row=0, column=1:-2
Enter the value for row=1, column=0:-3
Enter the value for row=1, column=1:-4
m[0][0]=1 m[0][1]=2
m[1][0]=3 m[1][1]=4

18. THANK YOU