Question

I’d like to do something like the following:

bool b = ...
string s = "Value of bool is: " + b ? "f" : "d";

All of the examples I’ve seen use cout, but I don’t want to print the string; just store it.

How do I do it? If possible, I’d like one example that assigns to a char * and one to a std::string.

Answer 1

If your compiler is new enough, it should have std::to_string:

string s = "Value of bool is: " + std::to_string(b);

This would of course append "1" (for true) or "0" (for false) to your string, not "f" or "d" as you want. The reason being that ther is no overload of std::to_string that takes a bool type, so the compiler converts it to an integer value.

You can of course do it in two step, first declare the string then append the value:

string s = "Value of bool is: ";
s += b ? "f" : "d";

Or do it almost like you do now, but explicitly create the second as a std::string:

string s = "Value of bool is: " + std::string(b ? "f" : "d");

Edit: How to get a char pointer from a std::string

This is done with the std::string::c_str method. But as noted by Pete Becker you have to be careful how you use this pointer, as it points to data inside the string object. If the object is destroyed so is the data, and the pointer, if saved, will now be invalid.