C Tutorial/Pointer/Address and Pointers
Address and Pointers
Address
- Each variable has two attributes: address and value.
- The address is the location in memory.
- In that locaton, the value is stored.
- During the lifetime of the variable, the address is not changed but the value may change.
Pointers
- A pointer is a variable whose value is an address.
- A pointer to an integer is a variable that can store the address of that integer.
10.2.Address and Pointers 10.2.1. Address and Pointers 10.2.2. <A href="/Tutorial/C/0200__Pointer/UsingPointers.htm">Using Pointers</a> 10.2.3. <A href="/Tutorial/C/0200__Pointer/Printaddressesusingplaceholders16luorp.htm">Print addresses using place holders %16lu or %p.</a>
Print addresses using place holders %16lu or %p.
#include <stdio.h>
main()
{
int a[5];
int i;
for(i = 0;i<5;i++)
{
a[i]=i;
}
for(i = 0;i<5;i++)
{
printf("value in array %d and address is %16lu\n",a[i],&a[i]);
}
for(i = 0;i<5;i++)
{
printf("value in array %d and address is %p\n",a[i],&a[i]);
}
}value in array 0 and address is 631656
value in array 1 and address is 631660
value in array 2 and address is 631664
value in array 3 and address is 631668
value in array 4 and address is 631672
value in array 0 and address is 9a368
value in array 1 and address is 9a36c
value in array 2 and address is 9a370
value in array 3 and address is 9a374
value in array 4 and address is 9a378
Using Pointers
Define a pointer: include a * before the name of the variable.
Get the address: use &.
#include <stdio.h>
main ()
{
int i;
int * ia;
i = 10;
ia = &i;
printf (" The address of i is %8u \n", ia);
printf (" The value at that location is %d\n", i);
printf (" The value at that location is %d\n", *ia);
*ia = 50;
printf ("The value of i is %d\n", i);
}The address of i is 631672 The value at that location is 10 The value at that location is 10 The value of i is 50
