字符串位移

public class Offset {

	public static  void swap(char [] chars , int position1 , int position2){
		if(position1 < chars.length && position2 < chars.length){
			char t = chars[position1];
			chars[position1] = chars[position2];
			chars[position2] = t;
		}
	}
	public static void reverse(char [] chars , int begin , int end){
		int i = begin;
		if (end < chars.length)
			while (i < end) {
				swap(chars , i++ , end--);
			}
	}
	public static void offset(char [] chars  , int n){
		n = n % chars.length;
		reverse(chars , 0 , n - 1);
		reverse(chars, n, chars.length - 1);
		reverse(chars, 0, chars.length - 1);
	}
	
	public static void main(String[] args) {
		char [] a = "abcdefg".toCharArray();
		offset(a , 3);
		for(char ch : a)
			System.out.print(ch);
	}
}