code: add subtraction of numbers

main.cpp

@@ -7,6 +7,7 @@ int main()
     cout << "Enter A and B" << endl;
     int a, b;
     cin >> a >> b;
-    cout << "A + B = " << a + b << endl;
+    cout << "A + B = " << a + b << '\n'
+        << "A - B = " << a - b << '\n';
     return 0;
 }