support bazel complie this project and format code.

practical_exercises/10_day_practice/day9/exception/7.cpp

@@ -0,0 +1,24 @@
+// Eg10-7.cpp
+#include <iostream>
+using namespace std;
+//内部再次throw异常的时候，函数不要带throw()
+void Errhandler(int n) {
+  try {
+    if (n == 1)
+      throw n;
+    cout << "all is ok..." << endl;
+  } catch (int n) {
+    cout << "catch an int exception inside..." << n << endl;
+    throw n; //再次抛出本catch捕获的异常
+  }
+}
+int main() {
+  try {
+    Errhandler(1);
+  } catch (int x) {
+    cout << "catch int an exception in main..." << x << endl;
+  }
+  cout << "....End..." << endl;
+  
+  return 0;
+}