can any explain example of pointer?

Answer 1

a pointer allows us to point back to a memory address
int a=45;//regular integer a that has a value of 45
int* p=&a;//integer pointer p that has the value of a's memory address
so far we've made int a with a value of 45, and an integer pointer p with a value of a's memory location.
so if we say something like
*p=34;
this is saying go to the memory address stored in p, in our case a, and set that value of 34. so if we now do something like
cout << a;
34 is printed to the screen instead of 45

Answer 2

#include<iostream>
using namespace std;
{
int a = 5; // here a holds the integer value that is 5
int *p; // p is a pointer to an integer
p=&a // here p is holding the memory address of a therefore ampersand (address of ) is used
cout<<a; // value of a will be printed i.e 5
cout<<p; // address of a will be printed
cout<<*p; // again value of a will be printed
return 0;
}