concatenate char array in C

Question

I have a a char array:

char* name = \"hello\";

I want to add an extension to that name to make it

hello.txt

Answer 1

asprintf is not 100% standard, but it's available via the GNU and BSD standard C libraries, so you probably have it. It allocates the output, so you don't have to sit there and count characters.

char *hi="Hello";
char *ext = ".txt";
char *cat;

asprintf(&cat, "%s%s", hi, ext);