indexOf, lastindexOf

public class IndexOfTest{
    public static void main(String[] args){

        String indexOfTestOne = "Hello world";
        String indexOfTestTwo = "         Hello world         ";     

        System.out.println( indexOfTestOne.indexOf("o") );  // 4
        System.out.println( indexOfTestOne.indexOf("x") );  // -1
        System.out.println( indexOfTestOne.indexOf("o",5) );  // 7
        System.out.println( indexOfTestTwo.indexOf("o") );  // 13
        System.out.println( indexOfTestTwo.indexOf("el") );  // 10

    }
}
0~시작

public class IndexOfTest{
    public static void main(String[] args){

        String indexOfTestOne = "Hello world";

        System.out.println( indexOfTestOne.lastIndexOf("o") );  // 7
        System.out.println( indexOfTestOne.lastIndexOf("x") );  // -1
        System.out.println( indexOfTestOne.lastIndexOf("o",5) );  // 4

    }
}