diff --git a/ch01/ex1_1.cpp b/ch01/ex1_1.cpp
index 905869df..9810ee22 100644
--- a/ch01/ex1_1.cpp
+++ b/ch01/ex1_1.cpp
@@ -1,4 +1,5 @@
 int main()
 {
+    cout<<"Hello world";
     return 0;
 }
diff --git a/ch01/ex1_10.cpp b/ch01/ex1_10.cpp
index 2bc61ef4..94ac8d29 100644
--- a/ch01/ex1_10.cpp
+++ b/ch01/ex1_10.cpp
@@ -1,11 +1,12 @@
 // prints the numbers from ten down to zero.(use while)
 
 #include <iostream>
-
+using namespace std;
 int main()
 {
     int i = 10;
-    while (i >= 0)
-        std::cout << i-- << " ";
+    while (i >= 0){
+    cout << i-- << " ";
+    }
     return 0;
 }