You'd either use a character array, or a string.
character arrays go something like this:
strings are like this:
char capital; //The brackets mean it's an array, the 20 means
//that you can have up to 20 values in your array
cin >> capital;
take a look here
#include <string> //This is at the top of your program(before main)
//in main do this:
string capital; //This makes a string variable and calls it captial.
cin >> capital; //This will get one word answers, but if there's a space it'll end there.
getline(cin, capital); //This gets a whole line for the capital string.