# Section 1.2 Variables and Arithmetic Expressions¶

## Question¶

This program uses the formula C=(5/9)(F-32) to print the Fahrenheit temperatures and their centigrade or Celsius equivalents.

## Program¶

```/* Temperature Conversion Program, Fahrenheit to Celsius */

#include<stdio.h>

/* print Fahrenheit-Celsius table for fahr = 0,20 ... 300 */

int main()
{
int lower,upper,step;
int celsius,fahr;

lower = 0;
upper = 300;
step = 20;

fahr = lower;

while( fahr <= upper)
{
celsius =  5 * (fahr - 32) / 9;
printf("%d\t%d\n",fahr,celsius);
fahr = fahr + step;
}

return 0;
}

```

## Explanation¶

In this program we are going to convert a given Fahrenheit temperature to Celsius temperature using the formula C=(5/9)(F-32) To do this we declare some variables in the beginning of the program so that they can be used in the later stages of the program. The variables in this program are: lower,upper,step, celsius,fahr.

The variable lower is assigned the value 0 similarly upper to 300, step to 20, and fahr to lower. So when the program enters the while loop it checks whether fahr <= upper is true if it is true then it assigns the variable celsius 5 * (fahr - 32) / 9 and then it prints out put.

### Understand¶

This document was updated on 26 Sep of 22