Using Pointers

int  i1;

int  i2;

int *ptr1;

int *ptr2;

i1 = 1;

i2 = 2;

ptr1 = &i1;//ptr1 points to address 0x1000

ptr2 = ptr1;//ptr2 takes address of ptr1 and so ptr2 points to   address 0x1000

*ptr1 = 3;//value of i1(to which ptr1 pointed becomes 3

i2 = *ptr2;//as i1=3,*ptr2=*ptr1=3,so i2 becomes 3