Defanging an IP Address — C++

// Time:  O(n)
// Space: O(1)

class Solution {
public:
    string defangIPaddr(string address) {
        string result;
        for (const auto& c : address) {
            if (c == '.') {
                result += "[.]";
            } else {
                result.push_back(c);
            }
        }
        return result;
    }
};