返回字符串的特定子字符串的第一个字母的索引

Question

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.

Answer 1

You can use as below

int indexOf(String str)

from your example string.

String s ="itiswhatitis";

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

Answer 2

"itiswhatitis".indexOf("is")

尝试这个

Answer 3

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

Answer 4

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