Why Celsius = 5 * (fahr-32)/9?

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There is a program to print Fahrenheit-celsius table as below.

#include <stdio.h>/* print Fahrenheit-celsius table for     Fahr = 0, ..., + */int main () {int Fahr, celsius;in t lower, upper, step;lower = 0;    /* Lower limit of temperature table */upper =;  /* Upper Limit */step =;    /* Step Size */fahr = Lower;while (Fahr <= Upper)  {Celsius = 5 * (fahr-32)/9;printf ("%d\t%d\n", Fahr, Celsius); Fahr = Fahr + Step;}}

The right part of the are the output of this program . The Celsius temperature is computed and assigned to the variablecelsiusBy the statement

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

The reason for multiplying by 5 and then dividing by 9 instead of just multiplying by 5/9 are that in C, as in many other L Anguages, integer division truncates: Any fractional part is discarded. Since 5 and 9 are integers, 5/9 would is truncated to zero and so all the Celsius temperatures would is reported as zero.

Referencethe C Programming Language

Why Celsius = 5 * (fahr-32)/9?