Java BigDecimal 的加法
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Addition for BigDecimal
提问by Sergio del Amo
I want to do some simple sums with some currency values expressed in BigDecimaltype.
我想用一些用BigDecimal类型表示的货币值做一些简单的求和。
BigDecimal test = new BigDecimal(0);
System.out.println(test);
test.add(new BigDecimal(30));
System.out.println(test);
test.add(new BigDecimal(45));
System.out.println(test);
Obviously I do not understand well the BigDecimalarithmetics, see output behind.
显然我对BigDecimal算术不太了解，请参阅后面的输出。
Test
0
0
0
Can anyone help me out?
谁能帮我吗？
采纳答案by Vincent Ramdhanie
The BigDecimalis immutable so you need to do this:
该BigDecimal所以你需要做的，这是不变的：
BigDecimal result = test.add(new BigDecimal(30));
System.out.println(result);
回答by ZZ Coder
BigInteger is immutable, you need to do this,
BigInteger 是不可变的，你需要这样做，
BigInteger sum = test.add(new BigInteger(30));
System.out.println(sum);
回答by Maurice Perry
BigDecimal test = new BigDecimal(0);
System.out.println(test);
test = test.add(new BigDecimal(30));
System.out.println(test);
test = test.add(new BigDecimal(45));
System.out.println(test);
回答by Ankur Goel
回答by nfechner
It's actually rather easy. Just do this:
其实还是比较容易的。只需这样做：
BigDecimal test = new BigDecimal(0);
System.out.println(test);
test = test.add(new BigDecimal(30));
System.out.println(test);
test = test.add(new BigDecimal(45));
System.out.println(test);
See also: BigDecimal#add(java.math.BigDecimal)
回答by MAK
//you can do in this way...as BigDecimal is immutable so cant set values except in constructor
BigDecimal test = BigDecimal.ZERO;
BigDecimal result = test.add(new BigDecimal(30));
System.out.println(result);
result would be 30
回答by Yatish
BigDecimal no = new BigDecimal(10); //you can add like this also
no = no.add(new BigDecimal(10));
System.out.println(no);
20
20
回答by snipersnack
BigDecimal demo = new BigDecimal(15);
It is immutable beacuse it internally store you input i.e (15) as final private final BigInteger intVal;and same concept use at the time of string creation every input finally store in
private final char value[];.So there is no implmented bug.
它是不可变的，因为它在内部存储您的输入，即 (15) 作为 final private final BigInteger intVal;字符串创建时使用的相同概念，每个输入最终存储在
private final char value[];.所以没有实现的错误。
回答by Paolo Leoncini
Just another example to add BigDecimals. Key point is that they are immutable and they can be initialized only in the constructor. Here is the code:
只是另一个例子来添加BigDecimals. 关键是它们是不可变的，只能在构造函数中初始化。这是代码：
import java.util.*;
import java.math.*;
public class Main {
public static void main(String[] args) {
Scanner sc;
boolean first_right_number = false;
BigDecimal initBigDecimal = BigDecimal.ZERO;
BigDecimal add1 = BigDecimal.ZERO;
BigDecimal add2 = BigDecimal.ZERO;
while (!first_right_number)
{
System.out.print("Enter a first single numeric value: ");
sc = new Scanner(System.in);
if (sc.hasNextBigDecimal())
{
first_right_number = true;
add1 = sc.nextBigDecimal();
}
}
boolean second_right_number = false;
while (!second_right_number)
{
System.out.print("Enter a second single numeric value: ");
sc = new Scanner(System.in);
if (sc.hasNextBigDecimal())
{
second_right_number = true;
add2 = sc.nextBigDecimal();
}
}
BigDecimal result = initBigDecimal.add(add1).add(add2);
System.out.println("Sum of the 2 numbers is: " + result.toString());
}
}
回答by Artur Krawczyk
You can also do it like this:
你也可以这样做：
BigDecimal A = new BigDecimal("10000000000");
BigDecimal B = new BigDecimal("20000000000");
BigDecimal C = new BigDecimal("30000000000");
BigDecimal resultSum = (A).add(B).add(C);
System.out.println("A+B+C= " + resultSum);
Prints:
印刷：
A+B+C= 60000000000
A+B+C= 60000000000
