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I think the main problem is that printf's %s formatter expects a C-style string, not a C++ string. All you'd have to do to fix this is:

printf ( "Topic %d is: %s.\n", i, static_cast<std::string>(my_list[i]).c_str() );

Note the addition of the .c_str() function call.

Also, you might want to change printf to ROS_INFO. All of the formatting is the same, but it has cool ROS functionality.

I think the main problem is that printf's %s formatter expects a C-style string, not a C++ string. All you'd have to do to fix this is:

printf ( "Topic %d is: %s.\n", i, static_cast<std::string>(my_list[i]).c_str() );

Note the addition of the .c_str() function call.

Also, you might want to change printf to ROS_INFO. All of the formatting is the same, but it has cool ROS functionality.

I think the main problem is that printf's %s formatter expects a C-style string, not a C++ string. All you'd have to do to fix this is:

printf ( "Topic %d is: %s.\n", i, static_cast<std::string>(my_list[i]).c_str() );

Note the addition of the .c_str() function call.

Also, you might want to change printf to ROS_INFO. All of the formatting is the same, but it has cool ROS functionality.

EDIT: Here's a quick explanation. Since printf is the output format used in C, not in C++, it expects that you'd be using C-style data structures. The %s formatter in C expects that you will pass in a const char*, which is C's representation of a string - an array of characters. In C++, however, the std::string data structure is more complex than a const char* and is its own type entirely. It's essentially the same as trying to use a double with %s. It's the wrong datatype, and therefore will not work. The .c_str() method of a C++ std::string returns a const char* of the string so that you can use it with C functions.