#include <stdio.h>

void print_array( int [], int );
void swap_by_value( int, int );
void swap_by_reference( int [], int, int );

int main() {

  int a, b, x, y;
  int size = 6;
  int list[] = { 0, 1, 2, 3, 4, 5 };

  a = 2;
  b = 4;

  printf( "\n" );
  printf( "Before calling swap_by_reference...\n" );
  print_array( list, size );

  swap_by_reference( list, a, b );
  printf( "\n" );

  printf( "After calling swap_by_reference...\n" );
  print_array( list, size );
  printf( "\n" );

  x = 10;
  y = 5;

  printf( "Before swap_by_value in main: \n" );
  printf( "  x = %d\n", x );
  printf( "  y = %d\n", y );
  printf( "\n" );

  swap_by_value( x, y );
  printf( "\n" );

  printf( "After swap_by_value in main: \n" );
  printf( "  x = %d\n", x );
  printf( "  y = %d\n", y );
  printf( "\n" );

  return 0;
}

void print_array( int list[], int num_list ) {

  int list_i;

  for ( list_i = 0; list_i < num_list; list_i++ ) {

    printf( " - list[%d]:  %d\n", list_i, list[ list_i ] );

  }
  printf( "\n" );

  return;
}

void swap_by_reference( int reference[], int index_1, int index_2 ) {

  int temp;

  printf( "Start of swap_by_reference...\n" );
  printf( "  reference[%d]:  %d\n", index_1, reference[ index_1 ] );
  printf( "  reference[%d]:  %d\n", index_2, reference[ index_2 ] );

  temp = reference[ index_1 ];
  reference[ index_1 ] = reference[ index_2 ];
  reference[ index_2 ] = temp;

  printf( "End of swap_by_reference...\n" );
  printf( "  reference[%d]:  %d\n", index_1, reference[ index_1 ] );
  printf( "  reference[%d]:  %d\n", index_2, reference[ index_2 ] );

  return;
}

void swap_by_value( int value_1, int value_2 ) {

  int temp;

  printf( "  Start of swap_by_value...\n" );
  printf( "    value_1 = %d\n", value_1 );
  printf( "    value_2 = %d\n", value_2 );

  temp = value_1;
  value_1 = value_2;
  value_2 = temp;

  printf( "  End of swap_by_value...\n" );
  printf( "    value_1 = %d\n", value_1 );
  printf( "    value_2 = %d\n", value_2 );

  return;
}