#include <stdio.h>  /* definitions and prototypes for printf() below */

/* sets the value of the double to
 * which the argument points to 2 */
static void
makeItTwo( double *value_pointer )
{
	*value_pointer = 2.0;
}

int
main()
{
	double value = 0.0;

	makeItTwo( &value );	/* pass the address of the variable */

	printf( "the value: %f\n", value );

	return 0;
}