while using substring to print a character pattern why has i been initialized to 1 instead of 0?-CodePudding

I understand this program the only doubt is in the part where i has been initialized to 1. As strings are stored like arrays the place at 0 should have the first character of the string right ? then why is it one. i would appreciate if you could also help me with understanding how substring method works :)).

sample input: SCHOOL sample output: S SC SCH SCHO SCHOO SCHOOL

 /*taking SCHOOL as example and print S SC SCH ...*/
import java.util.*;
public class substring
{
    public static void main(String args[])
    {
        Scanner sc = new Scanner(System.in);
        System.out.println("enter a string");
        String word = sc.next();
        
        int x= word.length();
        
        for( int i = 1; i<=x; i  )
        System.out.println(word.substring(0,i));
    }
    
}

CodePudding user response：

In the String.substring (int begIndex, int endIndex) method, endIndex doesn't index the last character of the substring. It indexes the character after the last character of the substring.

https://docs.oracle.com/javase/7/docs/api/java/lang/String.html#substring(int, int)

Thus, the length of the substring is endIndex-beginIndex