[英]What is the difference between BigDecimal movePointRight and scaleByPowerOfTen?
使用以下代码:
BigDecimal x = new BigDecimal("34.5678");
BigDecimal a = x.movePointRight(3);
BigDecimal b = x.scaleByPowerOfTen(3);
BigDecimal c = x.movePointRight(-3);
BigDecimal d = x.scaleByPowerOfTen(-3);
a和b均为34567.8,c和d均为0.0345678。 a.scale()
和b.scale
都是1, c.scale()
和d.scale()
都是7。
这两种方法在什么情况下产生不同的结果?
movePointRight
将防止出现负面比例,如果它导致一个。 scaleByPowerOfTen
不会阻止这种情况。 示例代码:
import java.math.BigDecimal;
public class BigDecimalScale {
public static void main(String... args) {
long base = 12345;
int scale = 4;
BigDecimal number = BigDecimal.valueOf(base, scale);
System.out.println(number);
BigDecimal pointRight = number.movePointRight(5);
System.out.println(pointRight + "; my scale is " + pointRight.scale());
BigDecimal scaleBy = number.scaleByPowerOfTen(5);
System.out.println(scaleBy + "; my scale is " + scaleBy.scale());
}
}
结果:
1.2345
123450; my scale is 0
1.2345E+5; my scale is -1
我找到了答案。 如果x被声明为
BigDecimal x = new BigDecimal("34.5678", new MathContext(4));
然后a的标度为0,但b的标度为-1。 a.toString()
给出34570, b.toString()
给出3.457E + 4
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