/*---------------------------------------------------*/
/*  Program chapter2_2                               */
/*                                                   */
/*  This program uses linear interpolation to        */
/*  compute the coefficient of lift for an angle.    */

#include <stdio.h>
#include <math.h>

int main(void)
{
   /*  Declare variables.  */
   double a, f_a, b, f_b, c, f_c;

   /*  Get user input from the keyboard.  */
   printf("Use degrees for all angle measurements. \n");
   printf("Enter first angle and lift coefficient: \n");
   scanf("%lf %lf",&a,&f_a);
   printf("Enter second angle and lift coefficient: \n");
   scanf("%lf %lf",&c,&f_c);
   printf("Enter new angle: \n");
   scanf("%lf",&b);

   /*  Use linear interpolation to compute new lift.  */
   f_b = f_a + (b-a)/(c-a)*(f_c - f_a);

   /*  Print new lift value.  */
   printf("New lift coefficient: %6.3f \n",f_b);

   /*  Exit program.  */
   return 0;
}
/*---------------------------------------------------*/