Write a recursive function that has two inputs, first and second, which are both strings (from ). The function should print all rearrangements of the letters in first, followed by second. For example, if first is the string "CAT" and second is the string "MAN", then the function would print the strings CATMAN, CTAMAN, ACTMAN, ATCMAN, TACMAN, and TCAMAN. The stopping case of the function occurs when the length of first has zero characters. We'll leave the recur- sive thinking up to you, but we should mention that two string member functions will make things go smoother. These member functions are void string::insert( size_type position, size_type number_of_copies, charc ); // Postcondition: The specified number of // copies of c have been inserted into the // string at the indicated position. Chars // that used to be at or after the given // position have been shifted right one spot. void string::erase (size_type position, size_type n); // Postcondition: n characters have been // removed from the string, beginning at the // specified position.