support bazel complie this project and format code.

practical_exercises/10_day_practice/day2/hanoi.cpp

@@ -0,0 +1,25 @@
+/* 汉诺塔.cpp */
+#include <iostream>
+using namespace std;
+void move(char A, char B);
+void hanoi(int n, char A, char B, char C);
+int main(int argc, char const *argv[]) {
+  cout << "请输入盘子数量：";
+  int disks;
+  cin >> disks;
+  hanoi(disks, 'A', 'B', 'C');
+  
+  return 0;
+}
+
+void move(char A, char B) { cout << A << "->" << B << endl; }
+
+void hanoi(int n, char A, char B, char C) {
+  if (n == 1) {
+    move(A, C);
+  } else {
+    hanoi(n - 1, A, C, B);
+    move(A, C);
+    hanoi(n - 1, B, A, C);
+  }
+}