Bracket the Dots in an IPv4 Address
Company: Google
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: easy
Interview Round: Other
### Problem
Given a valid IPv4 address string, return the same address with each dot replaced by `[.]`. Preserve all other characters and their order.
```cpp
class Solution {
public:
string defangIPaddr(string address);
};
```
### Examples
**Example 1:**
```text
Input: address = "10.20.30.40"
Output: "10[.]20[.]30[.]40"
Explanation: Each of the three dots is bracketed.
```
**Example 2:**
```text
Input: address = "0.0.0.0"
Output: "0[.]0[.]0[.]0"
Explanation: Digits remain unchanged.
```
### Constraints
- The given address is a valid IPv4 address.
### Contract considerations
The address is already valid. Only dots change; every digit and its order must be preserved.
```hint Read the boundary condition
Which characters are required to change, and which must remain exactly as they appeared?
```
### Boundary reminders
The address is already valid. Only dots change; every digit and its order must be preserved.
Overview: Bracket the Dots in an IPv4 Address. Given a valid IPv4 address string, return the same address with each dot replaced by [.].