Need help can someone please explain this?

Question

https://code.sololearn.com/crHkZV3l747v/?ref=app

Answer 1

Kim Jonas Cabugayan
String book = new String("123456789");
book.indexOf('4',4);

it finds '4' from index 4.
If it found then Index value is returned
else returns -1.

String book have '4' at index 3.
but From index 4, there is no '4' exist after that so returning -1.
edit:

Answer 2

Kim Jonas Cabugayan

indexOf('4', 4) means index of 4 will be search from position 4 but '4' is located at index '3' so -1

If you give ('4', 1) then searching will be start from index 1 so index of '4' will be 3

Answer 3

Thanks Jayakrishna🇮🇳 A͢J

Answer 4

Jayakrishna🇮🇳
Can you explain in layman terms?

Answer 5

I updated some more clear terms.. May it helps.. Kim Jonas Cabugayan