How to concatenate two strings in C

Question

I have a private class variable char name[10] that I'd want to add the.txt extension to so that I can access the file in the directory.

How do I go about it?

It's better to make a new string variable that retains the concatenated string.

Answer 1

If you were writing in C, and assuming name is a fixed-length array as you claim, you would have to do something like this:

char filename[sizeof(name) + 4];
strcpy (filename, name) ;
strcat (filename, ".txt") ;
FILE* fp = fopen (filename,...

Do you see why everyone recommends std::string?