diff --git a/day6/d1.cpp b/day6/d1.cpp
new file mode 100644
index 0000000..cb751b5
--- /dev/null
+++ b/day6/d1.cpp
@@ -0,0 +1,14 @@
+// 按位取反
+#include <iostream>
+
+using namespace std;
+
+int main()
+{
+    int n = 10;
+    cout << "~10 = " << ~n << endl; // 取反
+    n = -9;
+    cout << "~-9 = " << ~n << endl; // 取反
+
+    return 0;
+}