diff --git a/manualtest.cpp b/manualtest.cpp
index 355712d..a0094e6 100644
--- a/manualtest.cpp
+++ b/manualtest.cpp
@@ -1,5 +1,6 @@
 #include<iostream>
 #include<sstream>
+#include<cstring>
 #include"String.h"
 
 
@@ -18,5 +19,11 @@ int main()
     str2 = String(" tihihi");
     std::cout << str4 + str3 << std::endl;
     std::cout << ((str4 + str3)+=str2) << std::endl;
+    str4 += 'k';
+    std::cout << str4 << std::endl;
+    std::cout << str2+'k' << std::endl;
     std::cout << str4[0] << static_cast<const String>(str2)[1] << std::endl;
+    String str5 = str2;
+    str5[0] = 'i';
+    std::cout << str5 << std::endl;
 }
\ No newline at end of file