---
id: 5900f3941000cf542c50fea7
challengeType: 5
title: 'Problem 40: Champernowne"s constant'
videoUrl: ''
localeTitle: 问题40：Champernowne的常数
---
## Description
通过连接正整数创建无理小数： 0.12345678910 1 112131415161718192021 ...可以看出小数部分的第 12位是1.如果d n代表小数部分的第 n位，找到值以下表达式。 d 1 ×d 10 ×d 100 ×d 1000 ×d 10000 ×d 100000 ×d 1000000
## Instructions
## Tests
```yml
tests:
- text: champernownesConstant(100)应该返回5。
testString: 'assert.strictEqual(champernownesConstant(100), 5, "champernownesConstant(100) should return 5.");'
- text: champernownesConstant(1000)应该返回15。
testString: 'assert.strictEqual(champernownesConstant(1000), 15, "champernownesConstant(1000) should return 15.");'
- text: champernownesConstant(1000000)应该返回210。
testString: 'assert.strictEqual(champernownesConstant(1000000), 210, "champernownesConstant(1000000) should return 210.");'
```
## Challenge Seed
```js
function champernownesConstant(n) {
// Good luck!
return true;
}
champernownesConstant(100);
```
## Solution
```js
// solution required
```