how to swap values in variables in c

#include <stdio.h>
#include <stdlib.h>

int main()
{
  	//initialize variables
	int num1 = 10;
	int num2 = 9;
  	int tmp;
  	
  	//create the variables needed to store the address of the variables
  	//that we want to swap values
  	int *p_num1 = &num1;
  	int *p_num2 = &num2;
  
  	//print what the values are before the swap
  	printf("num1: %i\n", num1);
    printf("num2: %i\n", num2);
  
  	//store one of the variables in tmp so we can access it later
  	//gives the value we stored in another variable the new value
  	//give the other variable the value of tmp
  	tmp = num1;
  	*p_num1 = num2;
  	*p_num2 = tmp;

  	//print the values after swap has occured
   	printf("num1: %i\n", num1);
    printf("num2: %i\n", num2);
  	
	return 0;
}