String.charAt(int index)
...evaluates to the character
that is at location index
in the String.
The beginning character in a String is at location 0.
This program reverses the characters in a String. It does this by copying characters one at a time from right to left from the input String to the end of a reversed String.
public class ReverseTester { public static String reverse( String data ) { String rev = new String(); for ( int j=data.length()-1; j >= 0; j-- ) rev += data.charAt(j); return rev; } public static void main ( String[] args ) { System.out.println( reverse( "Hello" ) ); } }
Here is a sample run of this program:
C:\>java ReverseTester olleH