#include <stdio.h>
#include <math.h>
#include <stdlib.h>
void prob1(void);
void prob2(void);
 
double func(double x);
double norm(double *v, int k);
 
int main(void)
{
  int menu;
  printf("There are two functions: prob1() and prob2().\n");
  printf("Enter the function number to execute (1 or 2):");
  scanf("%d", &menu);
  /* form a switch to execute one function */
  switch(menu)
  {
   case 1:
      prob1();
      break;
   case 2:
      prob2();
      break;
   default:
  printf("prob%d() does not exist.\n", menu);
  }
  exit(0);
  }
 
  /*  Problem 1 */
  void prob1(void)
  {
    double x;
    printf("Here is Problem 1:\n");
    printf("Enter a double f-p constant:  "); 

    scanf("%lf",&x);
 
    printf("f(%f) = %f\n", x, func(x));
    return;
  }
 
  double func(double x)
  {
    if( x>= 4.0 ) return exp(x)-log10(x)+log(x);
    if( x<=-3.0 ) return 6*x - sinh(x); 
                  return x * sin(x) ; 
  }
 
 
  /*  Problem 2 */
  void prob2(void)
  {
    double v[15];
    int k;
    int i;

    printf("Here is  Problem 2:\n");
    printf("Enter the number of elements (<16): ");

    do {
      scanf("%d",&k); 
    } while (k > 15);


    printf("Enter %d double f-p constants", k);
    for( i=0; i<k; i++ ) {
     scanf("%lf",&v[i]);
    }
    return;

  }
 
  double norm(double *v, int k)
  {
 
}