Java Guava LongMath sqrt(long x, RoundingMode mode)用法及代碼示例

Guava LongMath類的sqrt(long x，RoundingMode模式)方法接受兩個參數，並根據第二個參數指定的舍入模式計算第一個參數的平方根。

用法:

public static long sqrt(long x, RoundingMode mode)

參數：此方法有兩個參數：

x:是其平方根的long值。
mode:是要進行舍入的舍入模式。

返回值：此方法返回x的平方根，並根據指定的舍入模式進行舍入。

異常：此方法引發以下參數：

IllegalArgumentException：如果x <0。
ArithmeticException：如果mode為RoundingMode.UNNECESSARY且sqrt(x)不是整數。

Enum RoundingMode

枚舉常量	描述
CEILING	舍入模式向正無窮大舍入。
DOWN	舍入模式向零舍入。
FLOOR	舍入模式向負無窮大舍入。
HALF_DOWN	除非兩個鄰居等距，否則舍入模式將朝“nearest neighbor”舍入。
HALF_EVEN	舍入模式向“nearest neighbor”舍入，除非兩個鄰居都等距，在這種情況下，向偶數鄰居舍入。
HALF_UP	除非兩個鄰居等距，否則舍入模式將朝“nearest neighbor”舍入。
UNNECESSARY	舍入模式可以斷言所請求的操作具有準確的結果，因此不需要舍入。
UP	舍入模式從零舍入。

下麵給出了一些示例，以更好地理解實現：

範例1：

// Java code to show implementation of 
// sqrt(long x, RoundingMode mode) method 
// of Guava's LongMath class 
  
import java.math.RoundingMode; 
import com.google.common.math.LongMath; 
  
class GFG { 
  
    // Driver code 
    public static void main(String args[]) 
    { 
        long x1 = 524; 
  
        // Using sqrt(long x, RoundingMode mode) 
        // method of Guava's LongMath class 
        // The RoundingMode HALF_EVEN rounds towards 
        // the nearest neighbor unless both neighbors 
        // are equidistant, in which case, round towards 
        // the even neighbor. 
        long ans1 
            = LongMath.sqrt(x1, 
                            RoundingMode.HALF_EVEN); 
  
        System.out.println("Square root of " + x1 
                           + " is:" + ans1); 
  
        long x2 = 316; 
  
        // Using sqrt(long x, RoundingMode mode) 
        // method of Guava's LongMath class 
        // The RoundingMode FLOOR rounds towards 
        // negative infinity. 
        long ans2 
            = LongMath.sqrt(x2, 
                            RoundingMode.FLOOR); 
  
        System.out.println("Square root of " + x2 
                           + " is:" + ans2); 
    } 
}

輸出：

Square root of 524 is:23
Square root of 316 is:17

範例2：

// Java code to show implementation of 
// sqrt(long x, RoundingMode mode) method 
// of Guava's LongMath class 
  
import java.math.RoundingMode; 
import com.google.common.math.LongMath; 
  
class GFG { 
  
    // Driver code 
    public static void main(String args[]) 
    { 
        int x = -65; 
  
        try { 
            // Using sqrt(long x, RoundingMode mode) 
            // method of Guava's LongMath class 
            // The RoundingMode HALF_EVEN rounds towards 
            // the nearest neighbor unless both neighbors 
            // are equidistant, in which case, round towards 
            // the even neighbor. 
  
            // This should throw "IllegalArgumentException" 
            // as x < 0 
            long ans1 = LongMath.sqrt(x, 
                                      RoundingMode.HALF_EVEN); 
        } 
        catch (Exception e) { 
            System.out.println(e); 
        } 
    } 
}

輸出：

java.lang.IllegalArgumentException:x (-65) must be >= 0

參考： https://google.github.io/guava/releases/20.0/api/docs/com/google/common/math/LongMath.html#sqrt-long-java.math.RoundingMode-

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注：本文由純淨天空篩選整理自Sahil_Bansall大神的英文原創作品 Java Guava | sqrt(long x, RoundingMode mode) of LongMath Class with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。