Java Division Two ways to keep the two digits after the decimal point summary of Floor,round and ceil of Java Math

Floor returns the largest integer not greater than
Round is the calculation of 4 5 in, when it is greater than its integer
Round method, which means "rounding", the algorithm is Math.floor (x+0.5), the original number is added 0.5 and then rounded down, so the result of Math.Round (11.5) is 12,math.round (-11.5) The result is-11.


Ceil is not less than his smallest integer

See Example

	Math.floor	Math.Round	Math.ceil
1.4	1	1	2
1.5	1	2	2
1.6	1	2	2
-1.4	-2	-1	-1
-1.5	-2	-1	-1
-1.6	-2	-2	-1

The test procedure is as follows:

[Java]View Plaincopyprint?

2. Public class MyTest {
4. public static void Main (string[] args) {
6. double[] Nums = { 1.4, 1.5, 1.6,-1.4,-1.5,-1.6};
8. For (double num:nums) {
10. Test (NUM);
12. }
14. }
18. private static void Test (double num) {
20. System.out.println ("math.floor (" + num + ") =" + Math.floor (num));
22. System.out.println ("math.round (" + num + ") =" + Math.Round (num));
24. System.out.println ("math.ceil (" + num + ") =" + Math.ceil (num));
26. }
28. }

Run results
Math.floor (1.4) =1.0
Math.Round (1.4) =1
Math.ceil (1.4) =2.0
Math.floor (1.5) =1.0
Math.Round (1.5) =2
Math.ceil (1.5) =2.0
Math.floor (1.6) =1.0
Math.Round (1.6) =2
Math.ceil (1.6) =2.0
Math.floor (-1.4) =-2.0
Math.Round (-1.4) =-1
Math.ceil (-1.4) =-1.0
Math.floor (-1.5) =-2.0
Math.Round (-1.5) =-1
Math.ceil (-1.5) =-1.0
Math.floor (-1.6) =-2.0
Math.Round (-1.6) =-2
Math.ceil (-1.6) =-1.0

http://blog.csdn.net/foart/article/details/4295645

1. Using the Math.Round () method:

Divides the number of two int, and the result retains two digits after the decimal point:

int a=1188;
int b=93;
Double C;

C= (Double) (Math.Round (A/b)/100.0);//This keeps 2 bits
Print Result: c=0.12

C=new Double (Math.Round (A/b)/1000.0);//This keeps 3 bits
Print Result: c=0.012


2. Another approach
Import Java.text.DecimalFormat;

DecimalFormat DF2 = new DecimalFormat ("###.00");//This is to keep 2 bits

DecimalFormat DF2 = new DecimalFormat ("###.000");//This is to keep 3 bits

SYSTEM.OUT.PRINTLN (Df2.format (variable of type double));

Ps:

The role of Math.Round ():

Double a=123.55
System.out.println (Math.Round (a));
Printed results: 124

http://blog.csdn.net/evatian/article/details/4398016

Java Division Two ways to keep the two digits after the decimal point summary of Floor,round and ceil of Java Math