/* 
 * Example of multiple-alternative decision of nested if 
 * Hanly and Koffman, 5e, Figure 4.10, page 184  
 */

#include <stdio.h> 

/* function prototype */
double comp_tax(double salary); 

/* Main function */ 
int 
main(void)
{
    double salary, tax; 

    printf("Input your annual salary >$ "); 
    scanf("%lf",&salary); 

    tax  = comp_tax(salary); 

    if (tax != -1.0) 
       printf("your tax is $%.2f", tax); 
    else
       printf("your salary is outside the table ranged");

    return 0; 
} 

/*
 * Function definition: Computes the tax due based on a tax table.
 * Pre : salary is defined.
 * Post: Returns the tax due for 0.0 <= salary <= 150,000.00;
 *       returns -1.0 if salary is outside the table range.
 */
double
comp_tax(double salary)
{
   double tax;

   if (salary < 0.0)
	tax = -1.0;
   else if (salary < 15000.00)	/* first range	*/
	tax = 0.15 * salary;
   else if (salary < 30000.00)	/* second range	*/
	tax = (salary - 15000.00) * 0.18 + 2250.00;
   else if (salary < 50000.00)	/* third range	*/
	tax = (salary - 30000.00) * 0.22 + 5400.00;
   else if (salary < 80000.00)	/* fourth range	*/
	tax = (salary - 50000.00) * 0.27 + 11000.00;
   else if (salary <= 150000.00)	/* fifth range	*/
	tax = (salary - 80000.00) * 0.33 + 21600.00;
   else
	tax = -1.0;

   return (tax);
}