Here you can find the source of ceil(double a)

Parameter | Description |
---|---|

a | a value |

public static double ceil(double a)

//package com.java2s; //License from project: Open Source License public class Main { /**/*from w w w .java 2s . c om*/ * Returns the smallest (closest to negative infinity) {@code double} value * that is greater than or equal to the argument and is equal to a * mathematical integer. Special cases: * <ul><li>If the argument value is already equal to a mathematical integer, * then the result is the same as the argument. <li>If the argument is NaN * or an infinity or positive zero or negative zero, then the result is the * same as the argument. <li>If the argument value is less than zero but * greater than -1.0, then the result is negative zero.</ul> Note that the * value of {@code Math.ceil(x)} is exactly the value of * {@code -Math.floor(-x)}. * * * @param a a value * @return the smallest (closest to negative infinity) floating-point value * that is greater than or equal to the argument and is equal to a * mathematical integer */ public static double ceil(double a) { returnMath.ceil(a); } }