javascript - 在 JavaScript 中根据 isOdd 定义 isEven

Question

我正在做 Codecademy 练习:

Remember the functions isOdd and isEven from Exercise 3.4?

We'd like you to code them here again! But this time, the aim is to define one function in terms of the other using the ! symbol.

Define isOdd, and then define isEven in terms of isOdd.

我尝试了几种我认为可行的不同方法，喜欢 console.log(!isOdd(1));和 (n !% 2 ===) ,他们都不对。

这是我的代码:

var isOdd = function (n)
{
 if (n % 2 ===0)
{
 return false;
} else {
 return true;
}
};
var isEven =function (n)
{
 if (n % 2 === 0)
{
 return true;
} else {
 return false;
}
};
console.log(isOdd(1));
console.log(isOdd(2));
console.log(isOdd(999));

Answer 1

很简单:

var isEven = function (n)
{
    return !isOdd(n);
}