https://leetcode.com/problems/to-lower-case/description/

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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"

'a' - 'A' = 32

class Solution {
public:
    string toLowerCase(string str) {
        int n = str.length();
        for (int i = 0; i < n; i++) {
            if (str[i] >= 'A' && str[i] <= 'Z') {
                str[i] += 32;
            }
        }
        return str;
    }
};