每日一题（6）

System.out.println(3.0 * 10 == 30.0);
System.out.println(3.14 * 10 == 31.4);
System.out.println(3.1415 * 10 == 31.415);

答案:
true
false
false

System.out.println(3.0 * 10);
System.out.println(3.14 * 10);
System.out.println(3.1415 * 10);
//输出
30.0
31.400000000000002
31.415000000000003

public static void main(String[] args) {
         int j = 0 ;
         for (int i = 0; i < 100 ; i++) {
             j = j++;
         }
         System.out.println(j);
     }