Can anyone explain to me how to reverse an integer without using array or String. I got this code from online, but not really understand why + input % 10 and divide again.
while (input != 0) {
reversedNum = reversedNum * 10 + input % 10;
input = input / 10;
}
And how to do use this sample code to reverse only odd number. Example I got this input 12345, then it will reverse the odd number to output 531.
public static double reverse(int num)
{
double num1 = num;
double ret = 0;
double counter = 0;
while (num1 > 1)
{
counter++;
num1 = num1/10;
}
while(counter >= 0)
{
int lastdigit = num%10;
ret += Math.pow(10, counter-1) * lastdigit;
num = num/10;
counter--;
}
return ret;
}
import java.util.Scanner;
public class ReverseOfInteger {
static Scanner input = new Scanner(System.in);
public static void main(String[] args) {
int x = input.nextInt();
System.out.print(helpermethod(x));
}
public static String helpermethod(int x) {
if (x == 0)
return "";
String a = String.valueOf(x % 10);
return a + helpermethod(x / 10);
}
}
I used String and I converted initially the int to String.Then I used the reverse method. I found the reverse of the number in String and then I converted the string back to int. Here is the program.
import java.util.*;
public class Panathinaikos {
public static void my_try()
{
Scanner input = new Scanner(System.in);
System.out.println("Enter the number you want to be reversed");
int number = input.nextInt();
String sReverse = Integer.toString(number);
String reverse = new StringBuffer(sReverse).reverse().toString();
int Reversed = Integer.parseInt(reverse);
System.out.print("The number " + number+ " reversed is " + Reversed);
}
}
public static void reverse(int number) {
while (number != 0) {
int remainder = number % 10;
System.out.print(remainder);
number = number / 10;
}
System.out.println();
}
What this does is, strip the last digit (within the 10s place) and add it to the front and then divides the number by 10, removing the last digit.
