#include <malloc.h>
#include <stdlib.h>

int main ( void )
{
  int *x = ( int * ) malloc ( sizeof ( int ) );
  int  y;

  if ( NULL != x )
  {
    *x = 1;

    //......

    free ( x );
    x = NULL;
  }
  else
  {
    return ( -1 );
  }

  y = ( *x );    //违背1

  return ( 0 );
}