Hi everyone if you can help.me understand this code in c++

Question

https://code.sololearn.com/crqe3xL0GqC2/?ref=app

Its the n-1 part why n-1 I'm kind of confused.

Answer 1

cuz the while loop is counting backwards.
also you can also write "n = n - 1" as "n--" or "n -= 1"

Answer 2

This function seems to add the substring of a given string to itself, and does so on each iteration. The value of n decreases by 1 after each iteration, so as you approach the end, the resulting substring being added to w gets shorter. As for why it is n-1, that really depends on what you are trying to achieve with the function. You can handtrace it to understand how it works, for example, calling the function with word = "hello" and n = 5 yields the following result:

repeatFront("hello", 5)
hello + w.substr(0, 4)
hello + hell + w.substr(0, 3)
hello + hell + hel + w.substr(0, 2)
hello + hell + hel + he + w.substr(0,1)
hello + hell + hel + he + h

hellohellhelheh