reverse them in pair
public class reverseDigitspair {
public int solution(int digit){
if(digit<10) return digit;
String str = String.valueOf(digit);
char[] string = str.toCharArray();
int i=0;
while(i<string.length-1){
char temp = string[i];
string[i] = string[i+1];
string[i+1] = temp;
i=i+2;
}
String newstring = new String(string);
return Integer.parseInt(newstring);
}
public static void main(String[] args){
reverseDigitspair rd = new reverseDigitspair();
System.out.print(rd.solution(12));
}
}