/************************************************************************* * Compilation: javac DigitReverser.java * Execution: java DigitReverser N * * Reverses the digits of a positive integer N using arithmetic. Then, * reverse it again using string concatenation. * * % java DigitReverser 12345 * 54321 * 12345 * *************************************************************************/ public class DigitReverser { public static void main(String[] args) { int N = Integer.parseInt(args[0]); // original integer // reverse using arithmetic int M = 0; while (N != 0) { M = (10 * M) + (N % 10); N = N / 10; } System.out.println(M); // reverse again using string concatenation String s = ""; while (M != 0) { int digit = M % 10; s = s + digit; M = M / 10; } System.out.println(s); } }