Java 中的大整数 intValueExact()方法,带示例

原文:https://www . geesforgeks . org/big integer-int value exact-method-in-Java-with-examples/

Java . math . big integer . intvalueexact()是在 Java 8 中引入的。这是一个内置函数,它将 BigInteger 的值转换为 int,并检查丢失的信息。如果 BigInteger 的值大于 2,147,483,647 或小于-2,147,483,648;该方法将抛出算术异常,因为大整数不适合整数范围。

语法:

public int intValueExact()

返回值:这个方法返回这个 BigInteger 的 int 值。

异常:如果 BigInteger 的值大于 2,147,483,647 或小于-2,147,483,648,则方法抛出算术异常;因为这个范围不适合 int 范围。

例:

Input: 4561561
Output: 4561561
Explanation: 4561561 is given as input which is bigInteger
and int value of 4561561 is 4561561

Input: -8546512
Output: -8546512
Explanation: -8546512 is given as input which is bigInteger 
and int value of -8546512 is -8546512

Input: 3000000000
Output: ArithmeticException
Explanation: When 3000000000 is tried to convert to int,
since 3000000000 > 2,147,483,647 (greater than a int's range), 
therefore it throws an arithmetic exception.

下面的程序说明了 BigInteger 类的 intValueExact()方法:

程序 1: 演示正数< 2,147,483,647

// Java program to demonstrate intValueExact()
// method of BigInteger Class

import java.math.*;

public class GFG {

    public static void main(String[] args)
    {
        // Creating a BigInteger object
        BigInteger big;
        big = new BigInteger("4561561");

        // print value of BigInteger
        System.out.println("BigInteger value : "
                           + big);

        // convert big to the int value
        int b1 = big.intValueExact();

        // print int value
        System.out.println("int converted value : "
                           + b1);
    }
}

的 intValueExact()方法输出:

BigInteger value : 4561561
int converted value : 4561561

程序二:演示负数> -2,147,483,648

// Java program to demonstrate intValueExact()
// method of BigInteger Class

import java.math.*;

public class GFG {

    public static void main(String[] args)
    {

        // Creating a BigInteger object
        BigInteger big = new BigInteger("-8546512");

        // print value of BigInteger
        System.out.println("BigInteger value : "
                           + big);

        // convert big to the int value
        int b1 = big.intValueExact();

        // print int value
        System.out.println("int converted value : "
                           + b1);
    }
}

的 intValueExact()方法输出:

BigInteger value : -8546512
int converted value : -8546512

程序 3: 演示负数<的 intValueExact()方法-2,147,483,648。它会抛出算术异常

// Java program to demonstrate intValueExact()
// method of BigInteger Class

import java.math.*;

public class GFG {

    public static void main(String[] args)
    {

        // Creating a BigInteger object
        BigInteger big = new BigInteger("-3000000000");

        // print value of BigInteger
        System.out.println("BigInteger value : "
                           + big);

        try {
            // convert big to the int value
            int b1 = big.intValueExact();

            // print int value
            System.out.println("int converted value : "
                               + b1);
        }
        catch (Exception e) {
            System.out.println("Exception: " + e);
        }
    }
}

输出:

BigInteger value : -3000000000
Exception: java.lang.ArithmeticException: BigInteger out of int range

程序 4: 演示正数> 2,147,483,647 的 intValueExact()方法。它会抛出算术异常

// Java program to demonstrate intValueExact()
// method of BigInteger Class

import java.math.*;

public class GFG {

    public static void main(String[] args)
    {

        // Creating a BigInteger object
        BigInteger big = new BigInteger("3000000000");

        // print value of BigInteger
        System.out.println("BigInteger value : "
                           + big);

        try {
            // convert big to the int value
            int b1 = big.intValueExact();

            // print int value
            System.out.println("int converted value : "
                               + b1);
        }
        catch (Exception e) {
            System.out.println("Exception: " + e);
        }
    }
}

输出:

BigInteger value : 3000000000
Exception: java.lang.ArithmeticException: BigInteger out of int range

参考:https://docs . Oracle . com/javae/8/docs/API/Java/math/biginteger . html # intvalueexact】