Stroustrup 5.9, exercise 4 (page 105)

this programme compiles but runs into some strange results, a semantic-
BUG is there. i even put some "std::cout" to know what is wrong but it
does something that i did NOT order it to do:

--------------- PROGRAMME -------------------
/* Stroustrup, 5.9 exercise 4

STATEMENT:
write a programme that swaps 2 integers. solve it
using 1st with pointers and then references.

METHOD:
1.) asks the user to input 2 integers
2.) swaps the value using pointers,
    prints 2 statements to show what it is doing
3.) prints the SWAPPED values
4.) swaps the vale sagain using References
5.) so after swapping 2 times we get the original input values.
*/

#include<iostream>

void swap_p(int* x, int* y);
void swap_r(int& x, int& y);

int main()
{
  using std::cout;
  using std::cin;
  using std::endl;

  int i;
  int j;

  cout << "Enter 1st integer: ";
  cin >> i;
  cout << "enter 2nd integer: ";
  cin >> j;

  cout << "i = " << i << '\t'
       << "j = " << j << endl;

  int* pi = &i;
  int* pj = &j;
  swap_p(pi, pj);

  cout << "\nvalues swapped using Poiners\n"
       << "i = " << i << '\t'
       << "j = " << j << endl;

  swap_r(i, j);

  cout << "\nswappe dusing Refrences\n"
       << "i = " << i << '\t'
       << "j = " << j << endl;

  return 0;
}

void swap_p(int* x, int* y)
{
  int temp_val = *x;
  x = y;
  std::cout << "------------------------------\n";
  std::cout << "x = " << *x << "\ty = " << *y <<'\n';

  *y = temp_val;
  std::cout << "x = " << *x << "\ty = " << *y <<'\n';
  std::cout << "------------------------------\n";
}

void swap_r(int& x, int& y)
{
  int temp_val = x;
  x = y;
  y = temp_val;
}

-------------- OUTPUT ------------------
[arch@voodo tc++pl]$ g++ -ansi -pedantic -Wall -Wextra 5.9_ex-04.cpp
[arch@voodo tc++pl]$ ./a.out
Enter 1st integer: 3
enter 2nd integer: -2
i = 3 j = -2
------------------------------
x = -2 y = -2
x = 3 y = 3
------------------------------

values swapped using Poiners
i = 3 j = 3

swappe dusing Refrences
i = 3 j = 3
[arch@voodo tc++pl]$

------------------------------
x = -2 y = -2
x = 3 y = 3
------------------------------

1st line is fine but why does it change value of "x" in 2nd line.i did
not do anything to "x"

?