script.js

const calculateTemp = () => {
   const numberTemp = document.getElementById('temp').value;
   //console.log(typeof(parseInt(numberTemp)));
   const tempSelected = document.getElementById('temp_diff');
   const valueTemp = tempSelected.value;
    
    //const valueTemp = tempSelected.options[tempSelected.selectedInedex].value;
   //console.log(valueTemp);

   const celToFah = (cel) => {
       let fahrenheit = ((cel/5)*9)+32;
       let fahrenheitFinal = fahrenheit.toFixed(2);
       return fahrenheitFinal;
   }

   const fahToCel = (fah) => {
       let celsius = ((fah-32)*5)/9;
       let celsiusFinal = celsius.toFixed(2);
       return celsiusFinal;
   }
   
   let resultTemp;
   if(valueTemp == "cel"){
       resultTemp= celToFah(parseInt(numberTemp));
       document.getElementById('resultContainer').innerHTML = `= ${resultTemp} °Fahrenheit` ;
   } else{
       resultTemp= fahToCel(parseInt(numberTemp));
       document.getElementById('resultContainer').innerHTML = `= ${resultTemp} °Celsius` ;
   }
}


const calculator = () => {
    const operation = document.getElementById('cal');
    const valOpe = operation.value;

    const number1 = parseInt(document.getElementById('num1').value);
    const number2 = parseInt(document.getElementById('num2').value);

    switch(valOpe){
        case 'sum':
            document.getElementById('resultCalculator').innerHTML = `= ${number1+number2}` ;
            break;
        case 'subs':
            document.getElementById('resultCalculator').innerHTML = `= ${number1-number2}` ;
            break;
        case 'mult':
            document.getElementById('resultCalculator').innerHTML = `= ${number1*number2}` ;
            break;
        case 'div':
            if(number2==0){
                document.getElementById('resultCalculator').innerHTML = `Error!` ;
            } else{
                let division = number1/number2;
                let diviFinal = division.toFixed(2);
                document.getElementById('resultCalculator').innerHTML = `= ${diviFinal}` ;
            }
            break;
        case 'modu':
            if(number2==0){
                document.getElementById('resultCalculator').innerHTML = `Error!` ;
            } else{
            document.getElementById('resultCalculator').innerHTML = `= ${number1%number2}` ;
            }
            break;
        default:
            return;
    }
}


const changeNumber = () => {
   const numberCh = document.getElementById('numChange').value;

   const SysSelected = document.getElementById('numSys');
   const valueNumCh = SysSelected.value;

   const binToDec = (bin) =>{
       let decimal = parseInt(bin, 2);
       return decimal;
   }

   const decToBin = (dec) => {
        // let binaryNum = new Array(32);

        // let i=0;
        // while(dec>0){
        //    binaryNum[i] = dec % 2;
        //    dec = Math.floor(dec / 2);
        //    i++;
        // }
        // for (let j = i - 1; j >= 0; j--){
        //    document.write(binaryNum[j]);
        // }

       var bNum = 0;
       var cnt =0;
       while(dec!=0){
           var rem = dec %2;
           var c = Math.pow(10,cnt);
           bNum += rem * c;
           dec = parseInt(dec/2);

           cnt++;
       }
       return bNum;
   }

   let resultNumCh;
   if(valueNumCh == 'dec'){
       resultNumCh= decToBin(parseInt(numberCh));
       document.getElementById('resultNumChange').innerHTML = `Binary= ${resultNumCh} ` ;
   } else{
       resultNumCh= binToDec(parseInt(numberCh));
       document.getElementById('resultNumChange').innerHTML = `Decimal= ${resultNumCh} ` ;
   }

}


const calculatePower = () =>{
    const base = parseInt(document.getElementById('base').value);
    const index = parseInt(document.getElementById('index').value);

    const power = (x,n) =>{
        return (Math.pow(x,n));
    }
    let resultPow = power(base,index);
    document.getElementById('resultPower').innerHTML = `${base}^${index}=${resultPow}` ;

}


const calculateFact = () =>{
    const fact = parseInt(document.getElementById('fact').value);

    const factorial = (n) =>{
            let fac =1;
            for(var i=n;i>0;i--){
                fac = fac*i;
        }
        return fac;
    }
    let resultFact;
    if(fact<0){
        document.getElementById('resultFact').innerHTML = `Error!` ;
    } else if(fact == 0){
        document.getElementById('resultFact').innerHTML = `Factorial= 1` ;
    } else{
        resultFact = factorial(parseInt(fact));
        document.getElementById('resultFact').innerHTML = `Factorial= ${resultFact}` ;
    }
}


const calculateLog = () =>{
    const log = parseInt(document.getElementById('log').value);

    const logarithm = (x) =>{
        return (Math.log(x));
    }
    let rasultLog;
    if(log<0){
        document.getElementById('resultLog').innerHTML = `Error!` ;
    } else if(log == 0){
        document.getElementById('resultLog').innerHTML = `-∞` ;
    } else{
        rasultLog = logarithm(parseInt(log));
        resultLogFinal = rasultLog.toFixed(2);
        document.getElementById('resultLog').innerHTML = `Logarithm= ${resultLogFinal}` ;
    }
}


const calculateBMI = () =>{
    const wei = parseInt(document.getElementById('wei').value);
    const hei = parseInt(document.getElementById('hei').value);

    const bmi = (w,h) =>{
        let hMet = 0.0254*h;
        return (w/(hMet*hMet));
    }
    let resultB = bmi(wei,hei);
    let resultBfinal = resultB.toFixed(2);
    document.getElementById('resultBMI').innerHTML = `Your BMI= ${resultBfinal}` ;
    if(resultBfinal < 18.50){
        document.getElementById('resultBMImsg').innerHTML = `You are Underweight` ;
    } else if(resultBfinal>= 18.50 && resultBfinal<= 24.99){
        document.getElementById('resultBMImsg').innerHTML = `You are Normal Weight` ;
    } else if(resultBfinal>= 25.00 && resultBfinal<= 29.99){
        document.getElementById('resultBMImsg').innerHTML = `You are Over Weight` ;
    } else if(resultBfinal>= 30.00 && resultBfinal<= 40.00){
        document.getElementById('resultBMImsg').innerHTML = `You are Obese` ;
    } else{
        document.getElementById('resultBMImsg').innerHTML = `You are Extreme Obese` ;
    }
    const img = document.createElement('img');
    img.src = 'converter/BMI-CHART.jpg';
    document.getElementById('bmiImg').appendChild(img);

}



function ageCalculator() {  
    var userinput = document.getElementById("DOB").value;  
    var dob = new Date(userinput);  
       
    if(userinput==null || userinput==''){  
      document.getElementById("message").innerHTML = "**Choose a date please!";    
      return false;   
    }   
    else {  
    var dobYear = dob.getYear();  
    var dobMonth = dob.getMonth();  
    var dobDate = dob.getDate();  
        
    var now = new Date();   
    var currentYear = now.getYear();  
    var currentMonth = now.getMonth();  
    var currentDate = now.getDate();  
       
    var age = {};  
    var ageString = "";  
     
    yearAge = currentYear - dobYear;  
     
    if (currentMonth >= dobMonth)   
      var monthAge = currentMonth - dobMonth;  
    else {  
      yearAge--;  
      var monthAge = 12 + currentMonth - dobMonth;  
    }  
   
    if (currentDate >= dobDate)    
      var dateAge = currentDate - dobDate;  
    else {  
      monthAge--;  
      var dateAge = 31 + currentDate - dobDate;  
  
      if (monthAge < 0) {  
        monthAge = 11;  
        yearAge--;  
      }  
    }  
     
    age = {  
    years: yearAge,  
    months: monthAge,  
    days: dateAge  
    };  
        
        
    if ( (age.years > 0) && (age.months > 0) && (age.days > 0) )  
       ageString = age.years + " years, " + age.months + " months, and " + age.days + " days old.";  
    else if ( (age.years == 0) && (age.months == 0) && (age.days > 0) )  
       ageString = "Only " + age.days + " days old!";    
    else if ( (age.years > 0) && (age.months == 0) && (age.days == 0) )  
       ageString = age.years +  " years old.<br> Happy Birthday!!";  
    else if ( (age.years > 0) && (age.months > 0) && (age.days == 0) )  
       ageString = age.years + " years and " + age.months + " months old.";  
    else if ( (age.years == 0) && (age.months > 0) && (age.days > 0) )  
       ageString = age.months + " months and " + age.days + " days old.";  
    else if ( (age.years > 0) && (age.months == 0) && (age.days > 0) )  
       ageString = age.years + " years, and" + age.days + " days old.";  
    else if ( (age.years == 0) && (age.months > 0) && (age.days == 0) )  
       ageString = age.months + " months old.";   
    else ageString = "Welcome to Earth! <br> It's first day on Earth!";   
   
    return document.getElementById("resultAge").innerHTML = ageString;   
               
  }  
}  



const solutionEq = () =>{
    const a = parseInt(document.getElementById('a').value);
    const b = parseInt(document.getElementById('b').value);
    const c = parseInt(document.getElementById('c').value);

    var disc = ((b*b) - (4*a*c));
    if(disc<0){
        document.getElementById('resultEqn').innerHTML = `The equation has no real solution` ;
    } else{
        var discRoot = Math.sqrt(disc);
        var sol1 = ((-b+discRoot)/(2*a));
        var sol2 = ((-b-discRoot)/(2*a));
        var resSol1 = sol1.toFixed(2);
        var resSol2 = sol2.toFixed(2);

        document.getElementById('resultEqn').innerHTML = `Solutions are ${resSol1} & ${resSol2}` ;

    }
}