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