/* a simple C program */
#include <stdio.h>
   
/* Declare conversion constant */
/* const tells C compiler this variable may not be changed */
const float CONVERSION_FACTOR = 1.056710f;   /*quarts to liters */
   
int
main (void)
{
  /* input */
  float quarts, liters;
  int numAssigned;
  printf ("Enter a value:  ");
  numAssigned = scanf ("%f", &quarts);

  /* validate input */
  if (numAssigned == 0) {
    printf ("Error: Unable to read number\n");
    return 1;
  } else if ( quarts < 0) {
    printf ("Error: Cannot have a negative quantity");
    return 1;
  }
  
  /* process value read */
  liters = quarts / CONVERSION_FACTOR;
   
  /* output */
  printf ("Result: %f quarts = %f liters\n", quarts, liters);
   
  return 0;
}  // main