Math.random

* Math.random 은 0 ~ 1사이의 실수를 발생시킨다.

1.
class ArrayEx1 {
   public static void main(String[] args) {
      int [] number = new int[10];
      for(int i = 0;i < number.length;i++) {
         number[i] = i;
         System.out.println(number[i]);
      }
      System.out.println();
      for(int i = 0;i < 100;i++) {
         int n = (int)(Math.random() * 10);
         int temp = number[0];
         number[0] = number[n];
         number[n] = temp;
      }
      for(int i = 0;i < number.length;i++)
         System.out.println(number[i]);
      }
}



2.
class ArrayEx1 {
   public static void main(String[] args) {
      int []number = new int[10];
      int []counter = new int[10];
      for(int i = 0;i < number.length;i++)
         System.out.print(number[i] = (int)(Math.random() * 10));
      System.out.println();
      for(int i = 0;i < number.length;i++)
         counter[number[i]]++;
      for(int i = 0;i < number.length;i++)
         System.out.println(i +"의 개수 : "+ counter[i]);
   }
}