Here you can find the source of sum(double... a)
public static double sum(double... a)
//package com.java2s; /******************************************************************************* * Copyright (c) 2010 BSI Business Systems Integration AG. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors:/*from ww w.j a v a 2s . co m*/ * BSI Business Systems Integration AG - initial API and implementation ******************************************************************************/ public class Main { public static double sum(double... a) { if (a == null) { return 0; } if (a.length == 0) { return 0; } double sum = 0; for (double d : a) { sum += d; } return sum; } public static long sum(long... a) { if (a == null) { return 0; } if (a.length == 0) { return 0; } long sum = 0; for (long d : a) { sum += d; } return sum; } }