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

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See also

• Suggest a Code Improvement: sec_1.2_fahr2cel.c

• Suggest a better explanation for sec_1.2_fahr2cel.rst

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This document was updated on 20 May of 22

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Exercise 1.2 - Experiment with printf

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Exercise 1.3 - Temperature Convertor