Java syntax index and java syntax Index

Java syntax index and java syntax Index

Public class MyApp {public static void main (String [] args) {System. out. print ("Hello World ");}}

How does a java array make the index value of the first element not 0?

The first index must be 0, which is not well discussed. When using it, + 1 is needed.
 
Java indexof syntax

T is the string to be queried, and 10 is the start position, that is, from the first to the start of the query, the returned 13 is the 10th position, that is, the 13th character is t, no matter whether there is a t before 10, if there is no t after 10,-1 is returned.

Last index of (t, 60) = 29 start position 60. If it cannot be found, it is pushed back. The result is 29.