/* --------------------------------------------------------------------- 
**  Figure 12.8:  A swap function that works.
** --------------------------------------------------------------------- 
*/
#include "tools.h"

void swap( double * fp1, double * fp2 );

void main( void )
{   
    double x = 10.2, y = 7;
    printf( "Before swap: x=%5.1g  y=%5.1g\n", x, y );
    swap( &x, &y );
    printf( "After swap: x=%5.1g  y=%5.1g\n", x, y );
}
/* ---------------------------------------------------- */
void 
swap( double * fp1, double * fp2 )
{   
    double swapper = *fp1;
    *fp1 = *fp2;
    *fp2 = swapper;
}   

/* Output ---------------------------------
Before swap: x= 10.2  y=  7.0
After swap:  x=  7.0  y= 10.2