Not sure why you get that, it compiled and worked fine for me (after I included <cstdlib> though, guessing you use visual c++ 2010?) What was the full error message?
Also, you don't need to make thechar an array, a simple char variable would have worked there. :)
And are do you want it to keep running and asking to put in more characters? Is there more code you are going to be writing into this program for other purposes later on? If not, what do you have a char pointer declared?