Question

Assuming:

std::string ToShow,NumStr;

The following displays “This is 19 ch00”:

ToShow = "This is nineteen ch";
ToShow.resize(ToShow.length()+0);
NumStr = "00";
ToShow += NumStr;
mvaddstr(15,0,ToShow.c_str());

And the following displays “This is 19 ch “:

ToShow = "This is nineteen ch";
ToShow.resize(ToShow.length()+1);
NumStr = "0";
ToShow += NumStr;
mvaddstr(16,0,ToShow.c_str());

In the second case, operator+= isn’t adding the string “0” to the end of ToShow. Does anyone know why?

Answer 1

My guess is:

You don’t specify the value to resize with, so after ToShow.Resize(ToShow.length()+1) your string looks like:

"This is nineteen ch\0"

And after += NumStr:

"This is nineteen ch\00"

which, after calling c_str, gets trimmed to the first \0 and looks like:

"This is nineteen ch"

(C strings are null-terminated, std::strings aren’t)

Try calling .resize(someLength, ' ') instead.