leetcode 709. To Lower Case(水，大写转小写）

Implement function ToLowerCase() that has a string parameter str, and returns the same string in lowercase.

Example 1:

Input: “Hello”
Output: “hello”
Example 2:

Input: “here”
Output: “here”
Example 3:

Input: “LOVELY”
Output: “lovely”

题意：大写转小写

知识点：

1. toLowerCase()大写转小写
2. toUpperCase()小写转大写

class Solution {
    public String toLowerCase(String str) {
        return str.toLowerCase();
    }
}