Java BigInteger multiply()用法及代碼示例

java.math.BigInteger.multiply(BigInteger val)用於計算兩個BigInteger的乘法。由於BigInteger類內部使用整數數組進行處理，因此對BigInteger對象的操作不如對基元進行的操作快。

用法:

public BigInteger multiply(BigInteger val)

參數：此方法接受參數val，該參數是要與該BigInteger相乘的值。

返回值：此方法返回一個保存乘法(此* val)的BigInteger。

下麵的程序用於說明BigInteger的multiply()方法。

示例1:

// Java program to demonstrate 
// multiply() method of BigInteger 
  
import java.math.BigInteger; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // BigInteger object to store result 
        BigInteger mult; 
  
        // For user input 
        // Use Scanner or BufferedReader 
  
        // Two objects of String created 
        // Holds the values to calculate the multiplication 
        String input1 = "012345678901234567"
                        + "654632498739473"; 
  
        String input2 = "0123456789012345"
                        + "61247612748612746"; 
  
        // Convert the string input to BigInteger 
        BigInteger a 
            = new BigInteger(input1); 
        BigInteger b 
            = new BigInteger(input2); 
  
        // Using multiply() method 
        mult = a.multiply(b); 
  
        // Display the result in BigInteger 
        System.out.println("The multiplication of\n"
                           + a + " \nand\n" + b + " "
                           + "\nis\n" + mult); 
    } 
}

輸出：

The multiplication of
12345678901234567654632498739473
and
12345678901234561247612748612746
is
152415787532388282591353462245536419067346861445890674421122858

示例2:

// Java program to demonstrate 
// multiply() method of BigInteger 
  
import java.math.BigInteger; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
        // BigInteger object to store result 
        BigInteger mult; 
  
        // For user input 
        // Use Scanner or BufferedReader 
  
        // Two objects of String created 
        // Holds the values to calculate the multiplication 
        String input1 = "012345678901234567"
                        + "8901234567890123"
                        + "4567890123456789"
                        + "0123456789012345"
                        + "6789012345678901"
                        + "654632498739473"; 
  
        String input2 = "0123456789012345"
                        + "6789012345678901"
                        + "2345678901234567"
                        + "8901234567890123"
                        + "4567890123456789"
                        + "61247612748612746"; 
  
        // Convert the string input to BigInteger 
        BigInteger a 
            = new BigInteger(input1); 
        BigInteger b 
            = new BigInteger(input2); 
  
        // Using multiply() method 
        mult = a.multiply(b); 
  
        // Display the result in BigInteger 
        System.out.println("The multiplication of\n"
                           + a + " \nand\n" + b + " "
                           + "\nis\n" + mult + "\n"); 
  
        // Using double to hold  the result 
        double d = Double.parseDouble(mult.toString()); 
  
        // Display the result in double 
        System.out.println("Using double, multiplication is "
                           + d); 
    } 
}

輸出：

The multiplication of
123456789012345678901234567890123456789012345678901234567890123456789012345678901654632498739473
and
123456789012345678901234567890123456789012345678901234567890123456789012345678961247612748612746
is
15241578753238836750495351562566681945008382873376009755225118122311263526910008985036532509972574264073578551235889967606442208008929541925721486305055001841778994861500543809890674421122858

Using double, multiplication is 1.5241578753238838E190

從上麵的示例中可以明顯看出，使用BigInteger時數據是完全精確的。

參考： https://docs.oracle.com/en/java/javase/12/docs/api/java.base/java/math/BigInteger.html#multiply(java.math.BigInteger)

相關用法

注：本文由純淨天空篩選整理自Rajnis09大神的英文原創作品 BigInteger multiply() Method in Java 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。