Exercise 1 program

 // define three int type assignment and the use of the ternary operator or acquiring achieve this if-else three numbers larger number
  int num1 = 10, = 21 is num2, num3 = -21;
  int max;
  IF (num1 > = && num1 num2> = num3) {
   max = num1;
  } the else IF (num2> = && num1 num2> = num3) {
   max = num2;
  } the else {
   max = num3;
  }
  System.out.println ( "maximum number of three is "+ max);
  .. 4 // declare two double programming variables and determining a first assignment and the second number is greater than 10.0 20.0 less than the number of prints or print two numbers and the number of two
  double D1 = 12.3;
  double = 32.1 D2;
  IF (D1> D2 && 10.0 <20.0) {
   
  } the else {

  }
  // two variable values to achieve the exchange 5 code
  String s1 = "Beijing";
  String S2 = "Nanjing";
  String TEMP = S1;
  S1 = S2;
  S2 = TEMP;
  System.out.println ( "the Hello World! ");