Denethor, you're wrong. Stop complaining and insulting the correct people because you're not getting anywhere. Back to the original question.
Code:
char a1='r';
char a2='f';
char mystring[2];
mystring[0]=a1;
mystring[1]=a2;
Whoever asked the original question, when you combine characters, you get a string which is an array of characters. If you don't know what an array is look at the tutorials on this site.