+=, a++, ++a

public class CalExer{
    public static void main(String[] args){
      int j = 10;
      int k = 20;
      int m = j + k;
      m += m;
      int n = m++;
      int l = ++m;

      System.out.println("m = " + m);// m=62
      System.out.println("n = " + n);// n=60
      System.out.println("l = " + l);// l=62
    }
  }