C Program to Convert Fahrenheit to Celsius

1. Introduction

Worldwide, temperatures are often measured using either the Celsius or Fahrenheit scales. While many countries use the Celsius scale, the United States predominantly uses Fahrenheit. Thus, having a tool that can easily convert between these scales can be invaluable. In this guide, we will devise a C program that undertakes the conversion of a temperature from Fahrenheit to Celsius.

2. Program Overview

Our program will perform the following tasks:

1. Prompt the user to input a temperature in Fahrenheit.

2. Calculate the equivalent Celsius value using the relevant conversion formula.

3. Display the converted temperature to the user.

3. Code Program

#include <stdio.h>  // Include the Standard I/O library

int main() {  // Commence the main program

    float fahrenheit, celsius;  // Declare float variables for the temperature readings

    // Prompt the user to input a temperature in Fahrenheit
    printf("Enter temperature in Fahrenheit: ");
    scanf("%f", &fahrenheit);  // Record the Fahrenheit temperature

    // Deploy the conversion formula to calculate the Celsius temperature
    celsius = (fahrenheit - 32) * 5/9;
    printf("The temperature in Celsius is: %.2f\n", celsius);

    return 0;  // Sign off from the program gracefully



Enter temperature in Fahrenheit: 77
The temperature in Celsius is: 25.00

4. Step By Step Explanation

1. #include <stdio.h>: This command incorporates the standard input and output library, granting us the liberty to employ functions like printf and scanf.

2. int main(): This is the primary function from which our program gets executed.

3. Variable Declaration:

  • fahrenheit and celsius: These float variables are designed to store the input and the derived temperatures, respectively.

4. User Input:

  • We kindly request the user to offer a temperature value in Fahrenheit.
  • Utilizing the scanf function, we capture and archive the user's input inside the fahrenheit variable.

5. Conversion to Celsius:

  • The formula to effect the transformation from Fahrenheit to Celsius is represented by: C = (F - 32) * 5/9, with C symbolizing the temperature in Celsius and F representing the Fahrenheit temperature.
  • Our code leverages this formula to discern the Celsius equivalent and keeps the outcome in the celsius variable.

6. Display the Result: We then showcase the deduced Celsius temperature to the user. 

With the assistance of this compact conversion formula, our program becomes a bridge, facilitating a seamless transition from Fahrenheit to Celsius, and vice-versa.