JavaScript：用户输入数字，直到输入0。确定每个数字的奇偶性，最后打印偶数和奇数的总数

Question

I also need to use the function to test the parity of the number. When I enter a few numbers (1,2,3,4 and then 0) the program shows "9, 0 ". I'm not sure why

let Even = 0;
let Odd = 0;
let a = parseInt(prompt("Enter a number:"));
while (a != 0 ) {
        a = parseInt(prompt("Enter a number:"));
        isEven(a);
            if(true){
                Even = Even + a};
            if(false){
                Odd = Odd + a};
                };
console.log(Even,Odd);

function isEven(value){
    if (value%2 == 0)
        return true;
    else
        return false;
}

Answer 1

Two mistakes inside your loop:

isEven(a);
if(true){
    Even = Even + a
};
if(false){
    Odd = Odd + a
};

The first one is that you're calling isEven and not using the result. In the if you're literally just using if(true) and if(false) , so you will always go in the first one and never in the second.

The second mistake is that each time you're adding the entered number a instead of 1, which is what you want if you need the amount of even/odd numbers.

So, keeping your (rather unusual) structure, you would have:

var test = isEven(a);
if(test === true){
    Even = Even + 1;
}
if(test === false){
    Odd = Odd + 1;
}

In a more traditional way, I would suggest:

if(isEven(a)){
    Even = Even + 1;
} else {
    Odd = Odd + 1;
}

Answer 2

Try using this.

You had some problems: 1.Suppose you type 1 the prompt will close and while first iteration will continue. You open a new prompt so 1 will never be calculated.

let a = parseInt(prompt("Enter a number:"));
while (a != 0 ) {
        a = parseInt(prompt("Enter a number:"));

2. You check IsEven(a) but never give that value to your conditions.

l

et Even = 0;
    let Odd = 0;
    let a = parseInt(prompt("Enter a number:"));
    while (a != 0 ) {
           var isEvenResult = isEven(a)
                if(isEvenResult){
                    Even += parseInt(a);
                    }
               else{
                    Odd += parseInt(a);
                    }
        a = parseInt(prompt("Enter a number:"));
                    }`enter code here`
    console.log(Even +','+ Odd);
    function isEven(value){
        if (value%2 == 0)
            return true;
        else
            return false;
    }