I need this to convert c to f but I keep receiving NaN as an answer cant figure what is going wrong

As stated above I need this to convert temperatures and show the respective picture but all i get now is NaN for the resulting conversion……………………………………………………………………………………………………………………………………………………………………………………………………………………
I have been trying to fix it but can’t seem to find the issue. …………………………………………………………………………………………………………………….
Can someone please help?

window.addEventListener("DOMContentLoaded", domLoaded);

function domLoaded() {
var convertButton = document.getElementById("convertButton");
var cInput = document.getElementById("cInput");
var fInput = document.getElementById("fInput");
var weatherImage = document.getElementById("weatherImage");
hideImage();//hide image initially
convertButton.addEventListener("click", convertTemperature);
cInput.addEventListener("input", () => {
    if (fInput.value.length > 0) {
        fInput.value = "";// to make other input empty when entering value in this
    }
})
fInput.addEventListener("input", () => {
    if (cInput.value.length > 0) {
        cInput.value = "";// to make other input empty when entering value in this
    }
})

function hideImage() {
    weatherImage.style.display = "none";
}

}

function convertTemperature() {
var cInput = document.getElementById("cInput");
var fInput = document.getElementById("fInput");
var weatherImage = document.getElementById("weatherImage");
var errorMessage = document.getElementById("errorMessage");
if (cInput.value.length > 0) {// if input not empty
    if (checkErrorInput(cInput.value)) {// runs while input is valid
        fInput.value = convertCtoF(parseFloat(cInput.value));
        showImage(parseFloat(fInput.value));// To show respective gifs
    }
} else if (fInput.value.length > 0) { // if input not empty
    if (checkErrorInput(fInput.value)) { // runs while input is valid
        cInput.value = convertFtoC(parseFloat(fInput.value));
        showImage(parseFloat(fInput.value));// To show respective gifs
    }
} else {
    errorMessage.innerText = "please enter temperature";
}

function checkErrorInput(input) {
    if (isNaN(parseFloat(input))) {
        errorMessage.innerHTML = input + " is not a number";
        return false;  // input is not valid throws error and returns false
    } else {
        errorMessage.innerHTML = "";
        return true;  // valid input
    }
}

function showImage(f) {
    if (fInput < 32) {
        weatherImage.src = "cold.png";// set src attribute to cold gif
        weatherImage.alt = "cold png";
    } else if (fInput >= 32 && f <= 50) {
        weatherImage.src = "cool.png";//set src attribute to gif
        weatherImage.alt = "cool png";
    } else {
        weatherImage.src = "warm.png"; //set src attribute to gif
        weatherImage.alt = "warm png";
    }
    weatherImage.style.display = "block";

}

}

document.addEventListener("DOMContentLoaded", domLoaded);//run when dom content is loaded



function convertCtoF(degreesCelsius) {
return cInput * (9 / 5) + 32;
}

function convertFtoC(degreesFahrenheit) {
return (fInput - 32) * 5 / 9;
}

Any help would be greatly appreciated!

>Solution :

cInput and fInput are domelements (tags) but, at

function convertCtoF(degreesCelsius) {
return cInput * (9 / 5) + 32;
}

function convertFtoC(degreesFahrenheit) {
return (fInput - 32) * 5 / 9;
}

they are used as variables, you need use cInput.value|fInput.value / use some variable and then assign it wherever you want.

Hope it will rectify yours.