3.2- random numbers

Java The method of obtaining random numbers ：

1. Use Random Object to obtain random numbers
   Specify the interval ： min ~ max
   int Type integer nextInt(max - min) + min
   double Type floating point number nextDouble() * (max - min) + min

        Random random = new Random();
		// obtain 0-10 A random number between 
        //  from 0-10 Get a random number in the range of  int Type of   contain 0, But not including 10
        int num = random.nextInt(10);

		// obtain 10-30 Random integer between 
		// Gets the random number of the specified interval ： min ~ max nextInt(max - min) + min
        int num1 = random.nextInt(30 - 10) + 10;

		// Get data of floating point type 
        double num3 = random.nextDouble();  // 0-1  Floating point data between 

		// Get the floating-point type data of the specified interval 
		//0 ~ 10  Between 
        double num4 = random.nextDouble() * (10 - 0) + 0;

		// obtain 20 - 50  Floating point data between 
        double num5 = random.nextDouble() * (50 - 20) + 20;

2. Use Math Medium random Method to complete
   The result itself is a 0 - 1 Floating point type data between
   Specify the interval ： min ~ max
   double Type floating point data ： Math.random() * (max - min) + min

        // 0-1  Floating point type data between 
	    double n = Math.random();  

		// Get the floating-point data of the specified interval 
        double n1 = Math.random() * (50 - 20) + 20;