To Lower Case

Description

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"

Discuss

直接遍历就可以

Code

class Solution {

    public String toLowerCase(String str) {

        if (str == null || str.length() == 0) { return null; }

        StringBuilder sb = new StringBuilder();

        for (int i = 0; i < str.length(); i++) {

            char c = str.charAt(i);

            if (c >= 'A' && c <= 'Z') {

                c += 32;

                sb.append(Character.toString((char)c));

                continue;

            }

            sb.append(c);

        }

        return sb.toString();

    }

}