pointer_basics.txt

pointers

suppose
int x=20;
will have address
pointer stores the address of that variables

define a ptr
int *ptr; //the address of that variable whose address it will store that should be integer

ptr=&x;

#include<iostream>
using namespace std;
int main()
{
int x = 20;

//declaring  + stroing address
 int *ptr;
ptr = &x;

//declare + storing address
int *ptr = &x;
//but use only one from above two 

cout<<ptr<<endl;//address 0*7ffeefbff59c
cout<<*ptr<<endl;//value kept on that position

//take char then int datatype should be chnges to char then only it will print
 char y = 'c';
char *pointer = &y;
cout<<*pointer<<endl; // c
cout<<pointer<<endl; //address 0*7ffeefbff59c

int *num = &x; //special type of thing for stroing address which is called pointer
} 

//ptr1 stores address and second star shows the address of pointer type 
int **ptr1;

int *ptr; //correct same
int* ptr;//correct same
int*ptr;//correct same

int *ptr = &x;
int **ptr1;
ptr1 = &ptr;
//ptr1 = &x; //show error because ptr1 can store the address of pointer type variable
cout<<ptr1<<endl;//address of ptr 0*7ffeefbff590
cout<<*ptr1<<endl;//address of int 0*7ffeefbff59c
cout<<**ptr1<<endl; // 20

suppose int a[] = {1,2,3,4,5};
int *ptr ;
ptr = a;//automatic stores address of first index;
//ptr = &a[0]; this is also correct

cout<<ptr<<endl;//address
cout<<*ptr<<endl;//1