添加文本转换器代码

others/C++/text converter/src/ROT13Converter.cpp

@@ -0,0 +1,13 @@
+#include "../include/ROT13Converter.hpp"
+
+std::string ROT13Converter::convert(const std::string& input) {
+    std::string result;
+    for (char c : input) {
+        if (isalpha(c)) {
+            char base = isupper(c) ? 'A' : 'a';
+            c = (c - base + 13) % 26 + base;
+        }
+        result += c;
+    }
+    return result;
+}