What is the complexity of this simple piece of code?

Question

I\'m pasting this text from an ebook I have. It says the complexity if O(n²) and also gives an explanation for it, but I fail to see how.

Question: What i

Answer 1

As the explanation given in the book, for ever word in the string array a new object of sentence gets created and that sentence object first copies the previous sentence and then traverses till the end of the array and then appends the new word, hence the complexity of n^2.

1. First 'n' to copy the previous sentence into a new object
2. Second 'n' to traverse that array and then append it

Hence n*n will be n^2.