/* ---------------------------------------------------------------------  
// Figure 9.1:  Functions, prototypes, and calls.
// --------------------------------------------------------------------- 
*/
#include "tools.h"                     
         
#define MIN    10.5 
#define MAX    87.0 
 
double f (double y);             /* Prototype for function f, defined below. */ 
double g (double y) { return( y * y + y ); }    /* Definition of function g. */

void main (void)                                       
{ 
    double x, z;                

    banner(); 
    printf( "\n Enter a value of x between %.2f and %.2f: ", MIN, MAX );  
    scanf( "%lg", &x );                                    
    z = f( x );                     
    printf( "\n The value of x * exp(x) is: %g \n", z );
    printf( "\n The value of x * x + x is: %g \n", g( x ) ); 
    bye();                        
}                                                     

/* ------------------------------------------------------------------- */   
/* -- Definition of function to calculate f = y * e to the power y. -- */  
double 
f (double y)
{ 
    return  y * exp(y) ;  
}