Update README.md

Author: kamyu104

README.md

@@ -205,7 +205,7 @@ Shell
 168| [Excel Sheet Column Title](https://leetcode.com/problems/excel-sheet-column-title/) | [Python](./Python/excel-sheet-column-title.py) | _O(logn)_ | _O(1)_ | Easy ||
 171| [Excel Sheet Column Number](https://leetcode.com/problems/excel-sheet-column-number/) | [Python](./Python/excel-sheet-column-number.py) | _O(n)_ | _O(1)_ | Easy  ||
 172| [Factorial Trailing Zeroes](https://leetcode.com/problems/factorial-trailing-zeroes/) | [Python](./Python/factorial-trailing-zeroes.py)  | _O(logn)_ | _O(1)_ | Easy         ||
-223| [Rectangle Area](https://leetcode.com/problems/rectangle-area/) | [Python](./Python/rectangle-area.py)  | _O(1)_ | _O(1)_ | Easy         ||
+223| [Rectangle Area](https://leetcode.com/problems/rectangle-area/) | [C++](./C++/rectangle-area.cpp)  [Python](./Python/rectangle-area.py)  | _O(1)_ | _O(1)_ | Easy         ||
 
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