Click here to download h20.c.

/***************************************************
H 0 State Program
 2

Write a program that reads in a temperature in the
form of NUMBER UNITS (e.g "123.02 Fahrenheit" or
"-75.0 Celsius") and returns "Gas", "Liquid", or
"Solid" depending on the state of H20 at that
temperature. Note: We'll assume standard pressure.

At standard pressure, we have ice at or below
32 Fahrenheit (0 Celsius), steam above 212 
Fahrenheit (100 Celsius), and water in between.
***************************************************/
#include "si204.h"

int main() {
  // Read user input temperature
  fputs("Enter temperature (NUMBER UNITS): ", stdout);
  double T = readnum(stdin);
  cstring units;
  readstring(units, stdin);

  // Get boiling and freezing temps depending on units
  double freeze = -1.0;
  double boil = -1.0;
  if (strcmp(units, "Fahrenheit") == 0) {
    freeze = 32.0;
    boil = 212.0;
  } else if (strcmp(units, "Celsius") == 0) {
    freeze = 0.0;
    boil = 100.0;
  } else {
    fputs("Please enter Fahrenheit or Celsius.\n", stdout);
    return 1; // indicates an error occured
  }

  if (T <= freeze) {
    fputs("Solid\n", stdout);
  } else if (T < boil) {
    fputs("Liquid\n", stdout);
  } else {
    fputs("Gas\n", stdout);
  }

  return 0;
}