diff --git a/C++/374.guess-number-higher-or-lower.cpp b/C++/374.guess-number-higher-or-lower.cpp
new file mode 100644
index 0000000..67f140d
--- /dev/null
+++ b/C++/374.guess-number-higher-or-lower.cpp
@@ -0,0 +1,27 @@
+/** 
+ * Forward declaration of guess API.
+ * @param  num   your guess
+ * @return 	     -1 if num is lower than the guess number
+ *			      1 if num is higher than the guess number
+ *               otherwise return 0
+ * int guess(int num);
+ */
+
+class Solution {
+public:
+    int guessNumber(int n) {
+        return gn(1,n);
+    }
+    int gn(long long l,int h){
+        switch(guess((l+h)/2)){
+            case 0:
+                return (l+h)/2;
+            case 1:
+                return gn((l+h)/2+1,h);
+            case -1:
+                return gn(l,(l+h)/2);
+        }
+        return 1;
+            
+    }
+};