arry of pointer and arithmetic operation

1. ARRAY OF POINTER
SUBMITTED BY:
IRUM
ABDULLAH
SUBMITTED TO:
MISS ZAINAB

2. WHAT IS ARRAY OF POINTER?
An array of pointer is an array in which eachelement is a pointer. Each
element in the array can store a memory address. The array can store
the memory addresses of different objects of data.

3. FOR EXAMPLE
#include<iostream.h>
#include<conio.h>
Void main()
{
clrscr()
Int*ptr[3],a,b,c;
Int i;
Ptr[0]=&a;
Ptr[1]=&b;
Ptr[2]=&c;
cout<<“enter three integer:”<<endl;
cin>>a>>b>>c;
cout<<“you enter the following values:n”;
for(i=0;i<3;i++)
cout<<*ptr[i]<<endl;
getch();
}

4. HOW ABOVE EXAMPLE WORK?
The above program declares an array of integer pointer and three
integer variables. Each element of pointer array refers to different
variable. The program input values to the variables and display them
using array of pointer.

5. Ptr[0] Ptr[1] Ptr[2]
a b c

6. ARITHMETIC OPERATOR ON POINTER

7. ARITHMETIC OPERATION ON POINTER
 Indirection (*): This operator is used to get the value from the pointed
address.
 Reference operator( &): This operator is used get the address of the
variable or pointer.
 Assignment ( =): You can assign the value to the pointer or value to the
address which is pointed by the pointer.
 Incrementing: You can add integer value to the pointer to point the
different memory location.
 Decrementing: You can subtract the integer value from the pointer to
point the different memory location.
 Comparison :This operation is valid only between two pointers that point
to the same array.

8. DECREMENT A POINTER
The same considerations apply to decrementing a
pointer, which decreases its value by the number of
bytes of its data type as shown below

9. PROGRAM BY USING DECREMENT ON A POINTER
#include <iostream>
using namespace std;
const int MAX = 3;
int main ()
{
int var[MAX] = {10, 100, 200};
int *ptr; // let us have address of the last element in pointer.
ptr = &var[MAX-1];
for (int i = MAX; i > 0; i--)
{
cout << "Address of var[" << i << "] = ";
cout << ptr << endl; cout << "Value of var[" << i << "] = ";
cout << *ptr << endl; // point to the previous location ptr--;
}
return 0;
}

10. INCREMENT A POINTER
We prefer using a pointer in our program instead of an array because the
variable pointer can be incremented, unlike the array name which
cannot be incremented because it is a constant pointer. The following
program increments the variable pointer to access each succeeding
element of the array −

11. PROGRAME USING INCREMENT OPERATOR
#include <iostream>
using namespace std;
const int MAX = 3;
int main ()
{
int var[MAX] = {10, 100, 200};
int *ptr; // let us have array address in pointer.
ptr = var;
for (int i = 0; i < MAX; i++)
{
cout << "Address of var[" << i << "] = ";
cout << *ptr << endl;
cout << "Value of var[" << i << "] = ";
cout << *ptr << endl; // point to the next location
ptr++;
}
return 0;
}

12. COMPARISON ON POINTER
 Pointers may be compared by using relational operators, such as ==, <,
and >. If p1 and p2 point to variables that are related to each other, such
as elements of the same array, then p1 and p2 can be meaningfully
compared.
 The following program modifies the previous example one by
incrementing the variable pointer so long as the address to which it
points is either less than or equal to the address of the last element of
the array, which is &var[MAX - 1] −

13. PROGRAM BY USING COMPARISON ON A POINTER
#include <iostream>
using namespace std;
const int MAX = 3;
int main ()
{
int var[MAX] = {10, 100, 200};
int *ptr; // let us have address of the first element in pointer.
ptr =&var;
int i = 0;
while ( ptr <= &var[MAX - 1] )
{
cout << "Address of var[" << i << "] = ";
cout << ptr << endl;
cout << "Value of var[" << i << "] = ";
cout << *ptr << endl; // point to the previous location ptr++;
i++;
}
return 0;