Java LongMath.checkedMultiply(int a, int b)用法及代碼示例

CheckedMultiply(long a，long b)是Guava LongMath類的方法，該方法接受兩個參數a和b並返回其乘積。

用法:

public static long checkedMultiply(long a, long b)

參數：該方法接受兩個long值a和b並計算其乘積。

返回值：該方法返回傳遞給它的long值的乘積，前提是它不會溢出。

異常：如果乘積(a-b)在有符號的long算術中溢出，則checkedMultiply(long a，long b)方法將引發ArithmeticException。

以下示例說明了上述方法的實現：

範例1：

// Java code to show implementation of 
// checkedMultiply(long a, long b) 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 a1 = 25; 
        long b1 = 36; 
  
        // Using checkedMultiply(long a, long b) 
        // method of Guava's LongMath class 
        long ans1 = LongMath.checkedMultiply(a1, b1); 
  
        System.out.println("Product of " + a1 + " and "
                           + b1 + " is:" + ans1); 
  
        long a2 = 150; 
        long b2 = 667; 
  
        // Using checkedMultiply(long a, long b) 
        // method of Guava's LongMath class 
        long ans2 = LongMath.checkedMultiply(a2, b2); 
  
        System.out.println("Product of " + a2 + " and "
                           + b2 + " is:" + ans2); 
    } 
}

輸出：

Product of 25 and 36 is:900
Product of 150 and 667 is:100050

範例2：

// Java code to show implementation of 
// checkedMultiply(long a, long b) method 
// of Guava's LongMath class 
  
import java.math.RoundingMode; 
import com.google.common.math.LongMath; 
  
class GFG { 
  
    static long findDiff(long a, long b) 
    { 
        try { 
  
            // Using checkedMultiply(long a, long b) method 
            // of Guava's LongMath class 
            // This should throw "ArithmeticException" 
            // as the product overflows in signed 
            // long arithmetic 
            long ans = LongMath.checkedMultiply(a, b); 
  
            // Return the answer 
            return ans; 
        } 
        catch (Exception e) { 
            System.out.println(e); 
            return -1; 
        } 
    } 
  
    // Driver code 
    public static void main(String args[]) 
    { 
        long a = Long.MIN_VALUE; 
        long b = 452; 
  
        try { 
  
            // Function calling 
            findDiff(a, b); 
        } 
        catch (Exception e) { 
            System.out.println(e); 
        } 
    } 
}

輸出：

java.lang.ArithmeticException:overflow

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

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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 | LongMath.checkedMultiply(int a, int b) method 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。