CHAPTER 35. TEMPERATURE CONVERTING CHAPTER 35. TEMPERATURE CONVERTING

Chapter 35

Temperature converting

Another very popular example in programming books for beginners is a small program that converts Fahrenheit temperature

to Celsius or back.

C=

5 ⋅(F−32)

9

We can also add simple error handling: 1) we must check if the user has entered a correct number; 2) we must check if the

Celsius temperature is not below− 273 (which is below absolute zero, as we may remember from school physics lessons).

Theexit()function terminates the program instantly, without returning to thecallerfunction.

35.1 Integer values

#include <stdio.h>

#include <stdlib.h>

int main()

{

int celsius, fahr;

printf ("Enter temperature in Fahrenheit:\n");

if (scanf ("%d", &fahr)!=1)

{

printf ("Error while parsing your input\n");

exit(0);

};

celsius = 5 * (fahr-32) / 9;

if (celsius<-273)

{

printf ("Error: incorrect temperature!\n");

exit(0);

};

printf ("Celsius: %d\n", celsius);

};

35.1.1 Optimizing MSVC 2012 x86.

Listing 35.1: Optimizing MSVC 2012 x86

$SG4228 DB 'Enter temperature in Fahrenheit:', 0aH, 00H

$SG4230 DB '%d', 00H

$SG4231 DB 'Error while parsing your input', 0aH, 00H

$SG4233 DB 'Error: incorrect temperature!', 0aH, 00H

$SG4234 DB 'Celsius: %d', 0aH, 00H

_fahr$ = -4 ; size = 4

_main PROC