add exit.cpp

+//
+// Created by mindyeoi on 2021/04/01.
+//
+
+#include <iostream>
+#include <string>
+using namespace std;
+
+
+int main()
+{
+    while(1)
+    {
+
+        string dasol;
+        cin >> dasol;
+        if(dasol == "exit")
+            break;
+    }
+    return 0;
+}