Redondeo en JAVA

[Alex13]

Hola quisiera saber como puedo redondear un numero a n lugares luego del punto en java.
Yo utilizo Math.rint(x*cant_cifras)/cant_cifras, pero por ejemplo si redondeo 3.0000 lo lleva a 3.0

[jelara]

Hi Alex,

For this, you can use String.format, wich can be used with a format very similar to C++'s printf: you pass a format string and a number, and it returns a string containing the number's representation in the desired format.

For example, if you want 4 figures after the decimal point, you would use:

Code: Select all

float result = 3.0f;
String output = String.format("%.4f", result);
System.out.println(output);

which would effectively display "3.0000" on the console.

I invite you to lookup the Javadocs for the String.format function, specifically the format string, so you can harness the power of this function and add it to your contestant's toolkit. Here is the URL:

http://download.oracle.com/javase/6/doc ... tml#syntax

By the way, remember to post only in English: not all of our users are Spanish-speakers!

[Alex13]

Ok thank´s.

[ldsierra]

Hi Alex13
You can also use this way

Code: Select all

System.out.printf("%.2f", 12.35642);     //output  12,36
System.out.printf("%.5f", 12.35);        //output  12,35000

[WIL]

Otra manera de redondear pero que no pone los 0s a la derecha es:

Code: Select all

double num=8.122800;
System.out.println(Math.ring(num*100)/100);

Esto redondea 2 lugares despues de la coma!!!

[jelara]

@WIL: That is like the code posted by Alex13, but he was precisely asking for a way to obtain the zeroes on the right.
@ldsierra: Wow, thanks! I haven't noticed there was an actual printf function

[axlluis]

Hi , how can i do the same but in c#??

[jelara]

Hi , how can i do the same but in c#??

Oh, in C# this is a piece of cake. The float.ToString function takes a parameter which controls the formatting... take a look at MSDN and all your doubts will be cleared.

[smicky125]

Heloo alex it is agreat information you share thanks lot all of you for the great help

[jlfernandez]

Hello, using the Format function is a great idea, i always have problem with that, thank...