Given a string in C++ such as " BCDAG" and a number k . Write a function in C++ that breaks this string up into strings of all posible combinations of size k and print it out with a space between them. Note the output must not be characters but srings.

Eg If k=2, the strings produced should be "BC" "CD" "DA" and "AG" .

NOTE:Only use For loops/conditional statements to solve this problem.