diff --git a/practical_exercises/key_exercises/动态数组.cpp b/practical_exercises/key_exercises/动态数组.cpp
index 7fb298a..5cb3343 100644
--- a/practical_exercises/key_exercises/动态数组.cpp
+++ b/practical_exercises/key_exercises/动态数组.cpp
@@ -1,5 +1,14 @@
 #include<iostream>
-char *sPtr;        		//����ַ�����ָ��       
-s="����"      
-sPtr = new char[strlen(s)+1];
-strncpy(sPtr,s;  
\ No newline at end of file
+#include<cstring>
+
+
+int main() {
+  
+  char *sPtr;        	 
+  const char* s="hello";
+  sPtr = new char[strlen(s)+1];
+  strncpy(sPtr,s,strlen(s)); 
+  std::cout << sPtr << std::endl;
+  delete sPtr;
+  return  0;
+}