support bazel complie this project and format code.

practical_exercises/10_day_practice/day10/file/12-5.cpp

@@ -0,0 +1,20 @@
+// Eg12-5.cpp
+#include <iomanip>
+#include <iostream>
+using namespace std;
+int main() {
+  char c[30] = "this is string";
+  double d = -1234.8976;
+  cout << setw(30) << left << setfill('*') << c << "----L1" << endl;
+  cout << setw(30) << right << setfill('*') << c << "----L2" << endl;
+  // showbase显示数值的基数前缀
+  cout << dec << showbase << showpoint << setw(30) << d << "----L3"
+       << "\n";
+  // showpoint显示小数点
+  cout << setw(30) << showpoint << setprecision(10) << d << "----L4"
+       << "\n";
+  // setbase(8)设置八进制
+  cout << setw(30) << setbase(16) << 100 << "----L5"
+       << "\n";
+  
+}