#define LOWER_LIMIT 0
#define HIGHER_LIMIT 50000

int main(void) {
   double fahr, cel;
   int limit_low = -1;
   int limit_high = -1;
   int step = -1;
   int max_step_size = 0;
   
   /* Read in lower, higher limit and step */
   while(limit_low < (int) LOWER_LIMIT) {
       printf("Please give in a lower limit, limit >= %d: ", (int) LOWER_LIMIT);
       scanf("%d", &limit_low);
   }
   while((limit_high <= limit_low) || (limit_high > (int) HIGHER_LIMIT)) {
       printf("Please give in a higher limit, %d < limit <= %d: ", limit_low, (int) HIGHER_LIMIT);
       scanf("%d", &limit_high);
   }
   max_step_size = limit_high - limit_low;
   while((step <= 0) || (step > max_step_size)) {
       printf("Please give in a step, 0 < step >= %d: ", max_step_size);
       scanf("%d", &step);
   }
   
   /* Initialise Celsius-Variable */
   cel = limit_low;
   
   /* Print the Table */
   printf("\nCelsius\t\tFahrenheit");
   printf("\n-------\t\t----------\n");
   while(cel <= limit_high) {
       fahr = (9.0 * cel) / 5.0 + 32.0;
       printf("%f\t%f\n", cel, fahr);
       cel += step;
   }
   printf("\n");
   
   return 0;
}