Elements of Programming Interviews (in Java)

    public static short countBits(int x) {
	    short numBits = 0;
	    while (x != 0) {
		    numBits += (x & 1);
		    x >>>= 1;
	    }
	    return numBits;
    }
    public static void main(String[] args) {
	System.out.println(countBits(15));
    }

  public static void main(String[] args) {
      System.out.println(6&4);
      System.out.println(1|2);
      System.out.println(8>>1);
      System.out.println(-16>>>2);
      System.out.println(1<<10);
      System.out.println(~0);
  }

  public static void main(String[] args) {
      System.out.println(Integer.MIN_VALUE);
      System.out.println(Float.MAX_VALUE);
      System.out.println(Double.SIZE);
      System.out.println(Boolean.TRUE);
  }

  public static void main(String[] args) {
      System.out.println(Double.valueOf("1.23"));
      System.out.println(Boolean.valueOf(true));
      System.out.println(Integer.parseInt("42"));
      System.out.println(Float.toString(-1.23F));
  }

  import static java.lang.Math.*;
  public static void main(String[] args) {
      System.out.println(abs(-34.5));
      System.out.println(ceil(2.17));
      System.out.println(floor(-34.5));
      System.out.println(min(-3,4.5));
      System.out.println(max(-3,4.5));
      System.out.println(pow(2.71,3.14));
      System.out.println(sqrt(225));
  }

  public static void main(String[] args) {
      char x = '6';
      System.out.println(Character.getNumericValue(x));
      System.out.println(x - '0');
      System.out.println(String.valueOf(123));
  }