Why Does My C Fahrenheit to Celsius Conversion Program Always Output 0?

C Program Encounters Unexpected Conversion Result: Fahrenheit to Celsius Discrepancy

A C program designed to convert Fahrenheit to Celsius encounters an unexpected output of zero. Here's the code along with the issue:

Code Snippet:

<code class="cpp">#include <iostream>
using namespace std;

int main() {
    float celsius;
    float fahrenheit;

    cout << "Enter Celsius temperature: ";
    cin >> celsius;
    fahrenheit = (5/9) * (celsius + 32);
    cout << "Fahrenheit = " << fahrenheit << endl;

    return 0;
}</code>

Issue Summary:

Upon execution, the program doesn't accurately convert Celsius to Fahrenheit and always outputs 0.

Problem Analysis:

The problem lies within the formula used to calculate Fahrenheit: fahrenheit = (5/9) * (celsius 32).

In this expression:

• 5/9 is computed as an integer division. In C , if both operands in a division operation are integers, the result is also an integer.
• Integer division truncates the result, which means any fractional part is discarded.

Therefore, 5/9 evaluates to 0, and the resulting Fahrenheit temperature is also 0, regardless of the input Celsius value.

Solution:

To resolve the issue, one needs to ensure that the division operation results in a floating-point number. This can be achieved by converting one of the operands to a floating-point type. The corrected code:

<code class="cpp">fahrenheit = (5.0/9) * (celsius + 32);</code>

With this modification, 5.0/9 becomes a floating-point division, preserving the fractional part and yielding the correct Fahrenheit conversion.

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