Java中的 BigInteger compareTo() 方法

Java.math.BigInteger.compareTo(BigInteger value)方法将此 BigInteger 与作为参数传递的 BigInteger 进行比较。

句法：

public int compareTo(BigInteger val)

参数：此方法接受一个强制参数val ，它是 BigInteger 与 BigInteger 对象进行比较。

返回：此方法返回以下内容：

• 0 ：如果此 BigInteger 的值等于作为参数传递的 BigInteger 对象的值。
• 1 ：如果此 BigInteger 的值大于作为参数传递的 BigInteger 对象的值。
• -1 ：如果此 BigInteger 的值小于作为参数传递的 BigInteger 对象的值。

例子：

Input: BigInteger1=2345, BigInteger2=7456
Output: -1
Explanation: BigInteger1.compareTo(BigInteger2)=-1.

Input: BigInteger1=9834, BigInteger2=7456
Output: 1
Explanation: BigInteger1.compareTo(BigInteger2)=1.

示例 1：下面的程序说明了 BigInteger 类的 compareTo() 方法，当两个 BigInteger 相等时

// Java program to demonstrate 
// compareTo() method of BigInteger
  
import java.math.BigInteger;
  
public class GFG {
  
    public static void main(String[] args)
    {
        // Creating 2 BigInteger objects
        BigInteger b1, b2;
  
        b1 = new BigInteger("321456");
        b2 = new BigInteger("321456");
  
        // apply compareTo() method
        int comparevalue = b1.compareTo(b2);
  
        // print result
        if (comparevalue == 0) {
  
            System.out.println("BigInteger1 "
                               + b1 + " and BigInteger2 "
                               + b2 + " are equal");
        }
        else if (comparevalue == 1) {
  
            System.out.println("BigInteger1 " + b1 + " 
                is greater than BigInteger2 " + b2);
        }
        else {
  
            System.out.println("BigInteger1 " + b1 + " 
                is lesser than BigInteger2 " + b2);
        }
    }
}

输出：

BigInteger1 321456 and BigInteger2 321456 are equal

示例 2：当 BigInteger1 大于 BigInteger2

// Java program to demonstrate 
// compareTo() method of BigInteger
  
import java.math.BigInteger;
  
public class GFG {
  
    public static void main(String[] args)
    {
        // Creating 2 BigInteger objects
        BigInteger b1, b2;
  
        b1 = new BigInteger("654321");
        b2 = new BigInteger("321456");
  
        // apply compareTo() method
        int comparevalue = b1.compareTo(b2);
  
        // print result
        if (comparevalue == 0) {
  
            System.out.println("BigInteger1 " + b1 + " 
                and BigInteger2 " + b2 + " are equal");
        }
        else if (comparevalue == 1) {
  
            System.out.println("BigInteger1 " + b1 + "
                is greater than BigInteger2 " + b2);
        }
        else {
  
            System.out.println("BigInteger1 " + b1 + " 
                is lesser than BigInteger2 " + b2);
        }
    }
}

输出：

BigInteger1 654321 is greater than BigInteger2 321456

示例 3：当 BigInteger1 小于 BigInteger2

// Java program to demonstrate 
// compareTo() method of BigInteger
  
import java.math.BigInteger;
  
public class GFG {
  
    public static void main(String[] args)
    {
        // Creating 2 BigInteger objects
        BigInteger b1, b2;
  
        b1 = new BigInteger("321456");
        b2 = new BigInteger("564321");
  
        // apply compareTo() method
        int comparevalue = b1.compareTo(b2);
  
        // print result
        if (comparevalue == 0) {
  
            System.out.println("BigInteger1 " + b1 + " 
                 and BigInteger2 " + b2 + " are equal");
        }
        else if (comparevalue == 1) {
  
            System.out.println("BigInteger1 " + b1 + " 
                  is greater than BigInteger2 " + b2);
        }
        else {
  
            System.out.println("BigInteger1 " + b1 + "
                 is lesser than BigInteger2 " + b2);
        }
    }
}

输出：

BigInteger1 321456 is lesser than BigInteger2 564321

参考：
BigInteger CompareTo() 文档