return index of the first letter of a specific substring of a string

问题

I am given a string and I wish to find out the index of the first character of a substring of that string whenever it appears the very first time in the parent string.

For example, given a string "itiswhatitis" and the substring "is", the output should be 2.

回答1:

You can use as below

int indexOf(String str)

from your example string.

String s ="itiswhatitis";

int index = s.indexOf("is");

回答2:

"itiswhatitis".indexOf("is")

Try this

回答3:

public static void main(String[] args) {
    int index = "itiswhatitis".indexOf("is");
    System.out.println(index);
}

回答4:

String str="itiswhatitis";
int index=str.indexOf("is");

来源：https://stackoverflow.com/questions/19025654/return-index-of-the-first-letter-of-a-specific-substring-of-a-string