leetCode169|转换为小写字母

示例 1：

输入: "Hello"
输出: "hello"
示例 2：

输入: "here"
输出: "here"
示例 3：

输入: "LOVELY"
输出: "lovely"

 

public  class ToLowerCaseTest2 {
    public static void main(String[] args) {
        String str = "Hello";
        String toLowerCase = toLowerCase(str);
        System.out.println("toLowerCase = " + toLowerCase);
    }

    public static String toLowerCase(String str) {
        if (str == null || str.length() == 0) {
            return str;
        }
        char[] chars = str.toCharArray();
        char[] result = new char[chars.length];
        int index = 0;
        for (int i = 0, len = chars.length; i < len; i++) {
            if (chars[i] >= 'A' && chars[i] <= 'Z') {
                result[index++] = (char) (chars[i] + 32);
            } else {
                result[index++] = chars[i];
            }
        }

        return String.valueOf(result);
    }
}