VC++异常捕获？？

1、

std：

 #include <string>
 #include<iostream> // for cerr
 //#include <stdexcept> // for what ?
 using namespace std;

 int _tmain(int argc, _TCHAR* argv[])
 {
     string s1("UIPower");
     char chA = s1[];

     try
     {
         char chD = s1.at();
     }
     catch(...)
     {
         printf("err\n");
     }

     printf("\n");
     try
     {
         char chD = s1.at();
     }
     catch(std::out_of_range &ex)
     {
         std::cerr << ex.what() << " Line:" << __LINE__ << " File:" << __FILE__ << endl;
     }

     printf("\n");
     try
     {
         char chD = s1.at();
     }
     catch(std::exception &ex)
     {
         std::cerr << ex.what() << " Line:" << __LINE__ << " File:" << __FILE__ << endl;
     }

     system("pause");
     return ;
 }

2、

C